Deposition mask package and deposition mask packaging method

ABSTRACT

A deposition mask package according to the present embodiment includes a receiving portion, a lid portion that faces the receiving portion, a deposition mask that is arranged between the receiving portion and the lid portion and has an effective region in which a plurality of through-holes is formed. The receiving portion has a first opposing surface facing the lid portion and a concave portion provided on the first opposing surface. The concave portion is covered by a first flexible film. The effective region of the deposition mask is arranged on the concave portion with the first flexible film interposed therebetween.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/JP2017/032938, filed Sep. 12, 2017.

TECHNICAL FIELD

The present embodiments relate to a deposition mask package obtained bypackaging a deposition mask including a plurality of through-holes and adeposition mask packaging method.

BACKGROUND ART

In recent years, it is required for display devices used in portabledevices, such as a smartphone and a tablet PC, to have high definition,for example, a pixel density of 400 ppi or higher. In addition, there isan increasing demand for adapting to ultra-high definition even withrespect to the portable devices. In this case, it is required for thedisplay devices to have a pixel density of, for example, 800 ppi orhigher.

Among the display devices, an organic EL display device has drawnattention due to good responsiveness, low power consumption, and highcontrast. As a method of forming pixels of the organic EL displaydevice, a method of forming pixels in a desired pattern using adeposition mask in which through-holes, arranged in a desired pattern,are formed is known.

Specifically, first, the deposition mask is brought into close contactwith a substrate for the organic EL display device, and then, adeposition step of introducing both the deposition mask and thesubstrate, in close contact with each other, into the deposition deviceto cause an organic material to be deposited on the substrate. In thiscase, it is required to precisely reproduce a position and a shape ofthe through-hole of the deposition mask in accordance with a design inorder to precisely prepare the organic EL display device having a highpixel density.

As a method of manufacturing the deposition mask, a method of forming athrough-hole in a metal plate by etching using a photolithographytechnique is known, for example, as disclosed in JP 5382259 B2. Forexample, a first resist pattern is first formed on a first surface ofthe metal plate, and a second resist pattern is formed on a secondsurface of the metal plate. Next, a region of the first surface of themetal plate that is not covered with the first resist pattern is etchedto form a first opening on the first surface of the metal plate.Thereafter, a region of the second surface of the metal plate that isnot covered with the second resist pattern is etched to form a secondopening on the second surface of the metal plate. At this time, it ispossible to form the through-hole penetrating the metal plate byperforming etching such that the first opening and the second openingcommunicate with each other. The metal plate for production of thedeposition mask is obtained, for example, by rolling a base materialsuch as an iron alloy.

In addition, as the method of manufacturing the deposition mask, amethod of manufacturing a deposition mask using a plating process isknown, for example, as disclosed in JP 2001-234385 A. For example, abase material having conductivity is produced first in the methoddescribed in JP 2001-234385 A. Next, a resist pattern is formed on thebase material with a predetermined gap therebetween. This resist patternis provided at positions where through-holes of the deposition mask needto be formed. Thereafter, a plating solution is supplied to the gap ofthe resist pattern to precipitate a metal layer on the base material byan electrolytic plating process. Thereafter, the deposition mask havingthe plurality of through-holes formed therein can be obtained byseparating the metal layer from the base material. When the platingprocess is used in this manner, it is possible to achieve highdefinition of the through-hole.

DISCLOSURE

When the deposition mask is sandwiched between a receiving portion and alid portion made of a plastic board or the like at the time oftransporting the deposition mask, a force is directly applied from thereceiving portion and the lid portion to the deposition mask. Thus,there is a problem that the deposition mask taken out after unpackingmay be plastically deformed. In addition, there is a possibility thatthe deposition mask is plastically deformed even by an impact receivedduring transportation.

In addition, there is a case where a plurality of deposition masks isstacked in one package when transporting the deposition mask in order toimprove transportation efficiency. In this case, there is a risk that adeposition mask may be plastically deformed at the time of taking outindividual deposition masks because a through-hole of one of adjacentdeposition masks and a through-hole of the other deposition mask arecaught by each other. In order to deal with such a risk, interposedpaper is inserted between a pair of adjacent deposition masks.

However, when a temperature change occurs during transportation, apositional shift is generated due to a difference between a dimensionalchange caused by thermal expansion of the deposition mask and adimensional change caused by thermal expansion of the interposed paperso that there is a problem that wrinkles or scratches are formed in thedeposition mask. In particular, when a thickness of the deposition maskis reduced, the deposition mask is likely to be plastically deformed.

When deposition materials are deposited on a substrate using adeposition mask, the deposition material adheres not only to thesubstrate but also to the deposition mask. For example, some of thedeposition materials are directed toward the substrate along a directionwhich is greatly inclined with respect to the normal direction of thedeposition mask, such deposition materials reach and adhere to a wallsurface of the through-hole of the deposition mask before reaching thesubstrate. In this case, it is conceivable that the deposition materialhardly adheres to a region of the substrate positioned in the vicinityof the wall surface of the through-hole of the deposition mask, and as aresult, a thickness of the adhering deposition material becomes smallerthan that in the other portion or a portion where the depositionmaterial does not adhere is generated. That is, it is conceivable thatdeposition in the vicinity of the wall surface of the through-hole ofthe deposition mask becomes unstable. As a result, the light emissionefficiency of the organic EL display device deteriorates.

In order to solve such a problem, it is conceivable to reduce thethickness of the metal plate used to manufacture the deposition mask.This is because it is possible to reduce the height of the wall surfaceof the through-hole of the deposition mask by lowering the thickness ofthe metal plate and to reduce the proportion of the deposition materialsadhering to the wall surface of the through-hole.

In this manner, the thickness of the deposition mask tends to becomethin in order to prevent the deterioration of the light emissionefficiency of the organic EL display device. Thus, it is desired toprevent plastic deformation during transportation even in the thindeposition mask.

An object of the present embodiments is to provide a deposition maskpackage and a deposition mask packaging method capable of preventingplastic deformation of a deposition mask during transportation.

The present embodiment relates to a deposition mask package including: areceiving portion; a lid portion that faces the receiving portion; adeposition mask that is arranged between the receiving portion and thelid portion and has an effective region in which a plurality ofthrough-holes is formed. The receiving portion has a first opposingsurface facing the lid portion and a concave portion provided on thefirst opposing surface. The concave portion is covered with a firstflexible film. The effective region of the deposition mask is arrangedon the concave portion with the first flexible film interposedtherebetween.

In the deposition mask package according to the present embodiment, endson both sides in a first direction of the deposition mask may bearranged on the first opposing surface of the receiving portion.

In the deposition mask package according to the present embodiment, adimension of the concave portion in a second direction orthogonal to thefirst direction may be larger than a dimension of the deposition mask inthe second direction.

In the deposition mask package according to the present embodiment, aninterposed sheet may be interposed between the deposition mask and thefirst flexible film, and a dimension of the interposed sheet in a seconddirection orthogonal to the first direction may be smaller than adimension of the concave portion in the second direction.

In the deposition mask package according to the present embodiment, thefirst flexible film may be a PET film.

In the deposition mask package according to the present embodiment, thefirst flexible film may be antistatic-coated.

In the deposition mask package according to the present embodiment, asecond flexible film may be interposed between the lid portion and thedeposition mask.

In the deposition mask package according to the present embodiment, thereceiving portion and the lid portion may be connected via a hingeportion.

The deposition mask package according to the present embodiment mayfurther include a sealing bag that seals the receiving portion and thelid portion.

The deposition mask package according to the present embodiment mayfurther include an impact sensor that detects an impact applied to thedeposition mask.

In addition, the present embodiment relates to a deposition maskpackaging method for packaging a deposition mask having an effectiveregion in which a plurality of through-holes is formed, the depositionmask packaging method including: preparing a receiving portion that hasa first opposing surface and a concave portion provided on the firstopposing surface and covered with a first flexible film; obtaining thedeposition mask placed on the receiving portion; arranging a lid portionon the deposition mask such that the receiving portion and the lidportion face each other; and sandwiching the deposition mask between thereceiving portion and the lid portion. In the arranging of thedeposition mask, the effective region of the deposition mask is placedon the concave portion with the first flexible film interposedtherebetween.

The present embodiment relates to a deposition mask package including: areceiving portion; a lid portion that faces the receiving portion; and adeposition mask stacked body arranged between the receiving portion andthe lid portion. The deposition mask stacked body includes: a depositionmask having a first surface, a second surface positioned opposite to thefirst surface, and a plurality of through-holes extending from the firstsurface to the second surface; and a plurality of interposed sheetsstacked on the first surface and the second surface of the depositionmask. A difference between a thermal expansion coefficient of thedeposition mask and the thermal expansion coefficient of the interposedsheet is 7 ppm/° C. or less.

In the deposition mask package according to the present embodiment, theinterposed sheet may have a dimension that enables a circumferentialedge of the interposed sheet to protrude from the deposition mask overthe entire circumference as viewed along a stacking direction of thedeposition mask.

In the deposition mask package according to the present embodiment, thedeposition mask and the interposed sheet may be formed using an ironalloy containing nickel in an amount of 30% by mass to 54% by mass.

In the deposition mask package according to the present embodiment, thedeposition mask and the interposed sheet may be formed using an ironalloy containing chromium.

In the deposition mask package according to the present embodiment, amaterial forming the interposed sheet may be identical to a materialforming the deposition mask.

In the deposition mask package according to the present embodiment, athickness of the interposed sheet may be 20 μm to 100 μm.

In the deposition mask package according to the present embodiment, athickness of the deposition mask may be 15 μm or more.

In the deposition mask package according to the present embodiment, thereceiving portion may have a first opposing surface facing the lidportion and a concave portion provided on the first opposing surface,ends on both sides in a first direction of the deposition mask may bearranged on the first opposing surface of the receiving portion, and adimension of the interposed sheet in a second direction orthogonal tothe first direction may be smaller than a dimension of the concaveportion in the second direction.

In addition, the present embodiment relates to a deposition maskpackaging method for packaging a deposition mask, which includes a firstsurface, a second surface positioned opposite to the first surface, anda plurality of through-holes extending from the first surface to thesecond surface, the deposition mask packaging method including:obtaining a deposition mask stacked body having the deposition mask andan interposed sheet stacked on the first surface and the second surfaceof the deposition mask, the deposition mask stacked body placed on thereceiving portion; arranging a lid portion on the deposition maskstacked body such that the receiving portion and the lid portion faceeach other; and sandwiching the deposition mask stacked body between thereceiving portion and the lid portion. A difference between a thermalexpansion coefficient of the deposition mask and a thermal expansioncoefficient of the interposed sheet is 7 ppm/° C. or less.

According to the present embodiment, it is possible to prevent thedeposition mask from being plastically deformed during thetransportation.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view illustrating a deposition device including a depositionmask device according to a present embodiment.

FIG. 2 is a cross-sectional view illustrating an organic EL displaydevice manufactured using the deposition mask device illustrated in FIG.1.

FIG. 3 is a plan view illustrating the deposition mask device accordingto the present embodiment.

FIG. 4 is a partial plan view illustrating an effective region of thedeposition mask illustrated in FIG. 3.

FIG. 5 is a cross-sectional view taken along the line V-V in FIG. 4.

FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 4.

FIG. 7 is a cross-sectional view taken along the line VII-VII of FIG. 4.

FIG. 8 is an enlarged cross-sectional view illustrating a through-holeillustrated in FIG. 5 and a region in the vicinity thereof.

FIG. 9 is a view illustrating a step of rolling a base material toobtain a metal plate having a desired thickness.

FIG. 10 is a view illustrating a step of annealing the metal plateobtained by rolling.

FIG. 11 is a schematic view for describing an example of a method ofmanufacturing a deposition mask as a whole.

FIG. 12 is a view illustrating a step of forming a resist film on themetal plate.

FIG. 13 is a view illustrating a step of bringing an exposure mask intoclose contact with the resist film.

FIG. 14 is a view illustrating a step of developing the resist film.

FIG. 15 is a view illustrating a first surface etching step.

FIG. 16 is a view illustrating a step of coating a first concave portionwith resin.

FIG. 17 is a view illustrating a second surface etching step.

FIG. 18 is a view illustrating the second surface etching stepsubsequent to FIG. 18.

FIG. 19 is a view illustrating a step of removing resin and a resistpattern from a long metal plate.

FIG. 20 is an enlarged plan view illustrating the effective region ofthe deposition mask.

FIG. 21 is a cross-sectional view of the effective region of FIG. 20 asviewed from the A-A direction.

FIG. 22 is a partially enlarged cross-sectional view of the depositionmask of FIG. 21.

FIG. 23 is a view for describing an example of a deposition maskmanufacturing method according to a present embodiment.

FIG. 24 is a view for describing an example of the deposition maskmanufacturing method according to the present embodiment.

FIG. 25 is a view for describing an example of the deposition maskmanufacturing method according to the present embodiment.

FIG. 26 is a view for describing an example of the deposition maskmanufacturing method according to the present embodiment.

FIG. 27 is a perspective view illustrating a deposition mask packageaccording to a present embodiment.

FIG. 28 is a longitudinal cross-sectional view illustrating thedeposition mask package of FIG. 27.

FIG. 29 is a transverse cross-sectional view illustrating the depositionmask package of FIG. 27.

FIG. 30 is a transverse cross-sectional view illustrating a developedstate of a packaging member of FIG. 27.

FIG. 31 is an enlarged longitudinal cross-sectional view of a depositionmask stacked body of FIGS. 28 and 29.

FIG. 32 is an enlarged cross-sectional view of the deposition maskstacked body of FIGS. 28 and 29.

FIG. 33 is a plan view illustrating the deposition mask placed on areceiving portion of FIGS. 28 and 29.

FIG. 34 is a view illustrating an example of a deposition mask packagingmethod according to a present embodiment.

FIG. 35 is a view illustrating an example of the deposition maskpackaging method according to the present embodiment.

FIG. 36 is a view illustrating an example of the deposition maskpackaging method according to the present embodiment.

FIG. 37 is a view illustrating an example of the deposition maskpackaging method according to the present embodiment.

FIG. 38 is a view illustrating an example of the deposition maskpackaging method according to the present embodiment.

FIG. 39 is a longitudinal cross-sectional view for describing a statewhere a downward force is applied to the deposition mask stacked body ofFIGS. 28 and 29.

FIG. 40 is a plan view illustrating a recess formed when a dimension ofan interposed sheet in a width direction is equal to or larger than adimension of a concave portion in the width direction.

FIG. 41 is a transverse cross-sectional view illustrating a modificationof the deposition mask package of FIG. 29.

FIG. 42 is a table illustrating transportation test results of Examplesof the present embodiment.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a present embodiment will be described with reference tothe drawings. Incidentally, in the drawings appended to thespecification of the present application, scales and horizontal andvertical dimension ratios are appropriately changed and exaggerated ascompared to actual ones thereof in order for convenience of illustrationand facilitating the understanding.

FIGS. 1 to 26 are views for describing a deposition mask according to apresent embodiment. In the following embodiment and modificationsthereof, a description will be given by exemplifying the deposition maskused for patterning of an organic material in a desired pattern on asubstrate when manufacturing an organic EL display device. However, thepresent embodiment is not limited to such applications but can beapplied to deposition masks used for various purposes.

Incidentally, in the present specification, the terms “plate”, “sheet”,and “film” are not distinguished from each other based solely ondifferences in nomenclature. For example, the “plate” is a concept thatalso includes a member which can be called a sheet or a film.

In addition, the “plate plane (a sheet plane or a film plane)” indicatesa surface that coincides with a plane direction of a target plate-likemember (a sheet-like member or a film-like member) in a case where thetarget plate-like (sheet-like or film-like) member is viewed widely as awhole. In addition, a normal direction used with respect to theplate-like (sheet-like or film-like) member indicates a normal directionwith respect to the plate plane (the sheet plane or the film plane) ofthe member.

In addition, terms, lengths, angles, and values of physicalcharacteristics specifying shapes, geometric conditions, physicalcharacteristics, and extent thereof used in the present specification(for example, the terms such as “parallel”, “orthogonal”, “same”, and“equivalent”) are interpreted including a range of extent where similarfunctions can be expected without being bound by strict meaning.

(Deposition Device)

First, a deposition device 90 that performs a deposition process todeposit a deposition material on an object will be described withreference to FIG. 1. As illustrated in FIG. 1, the deposition device 90includes a deposition source (for example, a crucible 94), a heater 96,and a deposition mask device 10. The crucible 94 contains a depositionmaterial 98 such as an organic light-emitting material. The heater 96heats the crucible 94 to evaporate the deposition material 98. Thedeposition mask device 10 is arranged to face the crucible 94.

(Deposition Mask Device)

Hereinafter, the deposition mask device 10 will be described. Asillustrated in FIG. 1, the deposition mask device 10 includes adeposition mask 20 and a frame 15 supporting the deposition mask 20. Theframe 15 supports the deposition mask 20 in the state of being pulled ina longitudinal direction (first direction) such that the deposition mask20 is not deflected. As illustrated in FIG. 1, the deposition maskdevice 10 is arranged inside the deposition device 90 such that thedeposition mask 20 faces a substrate which is an object to which thedeposition material 98 is attached, for example, an organic EL substrate92. In the following description, a surface of the deposition mask 20 onthe organic EL substrate 92 side is referred to as a first surface 20 a,and a surface on the opposite side of the first surface 20 a is referredto as a second surface 20 b. The frame 15 faces the second surface 20 bof the deposition mask 20.

As illustrated in FIG. 1, the deposition mask device 10 may include amagnet 93 arranged on a surface of the organic EL substrate 92 oppositeto the deposition mask 20. Since the magnet 93 is provided, thedeposition mask 20 can be brought into close contact with the organic ELsubstrate 92 by attracting the deposition mask 20 to the magnet 93 sideby a magnetic force.

FIG. 3 is a plan view illustrating a case where the deposition maskdevice 10 is viewed from the first surface 20 a side of the depositionmask 20. As illustrated in FIG. 3, the deposition mask device 10includes a plurality of the deposition masks 20 each having asubstantially rectangular shape in a plan view, and each of thedeposition masks 20 is welded and fixed onto the frame 15 at a pair ofends 20 e in the longitudinal direction of the deposition mask 20.

The deposition mask 20 includes a plurality of through-holes 25penetrating through the deposition mask 20. The deposition material 98that has vaporized from the crucible 94 and reached the deposition maskdevice 10 passes through the through-hole 25 of the deposition mask 20and adheres to the organic EL substrate 92. As a result, the depositionmaterial 98 can be deposited on the surface of the organic EL substrate92 in a desired pattern corresponding to positions of the through-holes25 of the deposition mask 20.

FIG. 2 is a cross-sectional view illustrating an organic EL displaydevice 100 manufactured using the deposition device 90 of FIG. 1. Theorganic EL display device 100 includes the organic EL substrate 92 and apixel containing the deposition material 98 provided in a pattern.

Incidentally, when it is desired to perform color display using aplurality of colors, the deposition devices 90 each of which has thedeposition mask 20 corresponding to each color are prepared, and theorganic EL substrate 92 is sequentially introduced into the respectivedeposition devices 90. As a result, for example, an organiclight-emitting material for red, an organic light-emitting material forgreen, and an organic light-emitting material for blue can besequentially deposited on the organic EL substrate 92.

Meanwhile, there is a case where the deposition process is performedinside the deposition device 90 which becomes high-temperatureatmosphere. In this case, the deposition mask 20, the frame 15, and theorganic EL substrate 92 held inside the deposition device 90 are alsoheated during the deposition process. At this time, each of thedeposition mask 20, the frame 15, and the organic EL substrate 92illustrates behavior of a dimensional change based on each thermalexpansion coefficient. In this case, if thermal expansion coefficientsof the deposition mask 20, the frame 15, and the organic EL substrate 92are greatly different from each other, misalignment due to a differencein dimensional changes among them is generated, and as a result,dimensional accuracy and positional accuracy of the deposition material98 adhering onto the organic EL substrate 92 deteriorate.

In order to solve such a problem, it is preferable that thermalexpansion coefficients of the deposition mask 20 and the frame 15 be thesame value as thermal expansion coefficient of the organic EL substrate92. For example, when a glass substrate is used as the organic ELsubstrate 92, an iron alloy containing nickel can be used as a mainmaterial of the deposition mask 20 and the frame 15. For example, it ispossible to use an iron alloy containing 30% by mass to 54% by mass ofnickel as a material of the metal plate forming the deposition mask 20.Specific examples of the iron alloy containing nickel can include aninvar material containing 34% by mass to 38% by mass of nickel, a superinvar material containing cobalt in addition to 30% by mass to 34% bymass of nickel, and a low thermal expansion Fe—Ni plated alloycontaining 48% by mass to 54% by mass of nickel. Incidentally, anumerical range expressed by the symbol “˜” includes numerical valuesplaced before and after the symbol “˜” in the present specification. Forexample, a numerical range defined by the expression “34 to 38% by mass”is identical to a numerical range defined by an expression “34% by massor higher and 38% by mass or lower”.

Incidentally, when temperature of the deposition mask 20, the frame 15,and the organic EL substrate 92 does not reach high temperature duringthe deposition process, it is not particularly necessary to set thermalexpansion coefficients of the deposition mask 20 and the frame 15 to thesame value as thermal expansion coefficient of the organic EL substrate92. In this case, a material other than the above-described iron alloymay be used as the material forming the deposition mask 20. For example,an iron alloy other than the above-described nickel-containing ironalloy such as an iron alloy containing chromium may be used. Forexample, an iron alloy referred to as a so-called stainless steel can beused as the iron alloy containing chromium. In addition, an alloy otherthan the iron alloy such as nickel and a nickel-cobalt alloy may beused.

(Deposition Mask)

Next, the deposition mask 20 will be described in detail. As illustratedin FIGS. 3 to 5, the deposition mask 20 includes an effective region 22in which a through-hole 25 extending from the first surface 20 a to thesecond surface 20 b is formed, and a peripheral region 23 surroundingthe effective region 22. The peripheral region 23 is a region configuredto support the effective region 22 and is not a region that allows adeposition material 98, which has been intended to be deposited on theorganic EL substrate 92, to pass therethrough. For example, theeffective region 22 is a region facing a display region of the organicEL substrate 92 in the deposition mask 20.

As illustrated in FIG. 3, the effective regions 22 has a substantiallyquadrangular shape in a plan view, more accurately, a substantiallyrectangular outline in a plan view, for example. Although notillustrated, each of the effective regions 22 can have outlines ofvarious shapes in accordance with a shape of the display region of theorganic EL substrate 92. For example, each of the effective regions 22may have a circular outline.

As illustrated in FIG. 3, a plurality of the effective regions 22 isarranged at predetermined intervals along the longitudinal direction ofthe deposition mask 20. The single effective region 22 corresponds toone display region of the organic EL display device 100. Thus, it ispossible to deposit the organic EL display device 100 with multiplesurfaces according to the deposition mask device 10 illustrated inFIG. 1. As illustrated in FIG. 4, a plurality of the through-holes 25 inthe effective region 22 is regularly arranged at predetermined pitchesalong two directions orthogonal to each other.

Hereinafter, shapes of the through-hole 25 and a peripheral part thereofwill be described in detail.

(Deposition Mask Manufactured by Etching Process) Here, the shapes ofthe through-hole 25 and the peripheral part thereof in the case wherethe deposition mask 20 is formed by an etching process will bedescribed.

FIG. 4 is an enlarged plan view illustrating the effective region 22from the second surface 20 b side of the deposition mask 20 manufacturedby the etching process. As illustrated in FIG. 4, the plurality ofthrough-holes 25 formed in each of the effective regions 22 are arrayedat predetermined pitches along the two directions orthogonal to eachother in the effective region 22 in the illustrated example. An exampleof the through-hole 25 will be described in more detail mainly withreference to FIGS. 5 to 7. FIGS. 5 to 7 are cross-sectional views takenalong a direction V-V to a direction VII-VII of the effective region 22of FIG. 4, respectively. Incidentally, a boundary line between theeffective region 22 and the peripheral region 23 illustrated in FIGS. 5to 7 is an example, and a position of this boundary line is arbitrary.For example, this boundary line may be arranged in a region where thesecond concave portion 35 is not formed (the left side of the secondconcave portion 35 on the leftmost side in FIG. 5).

As illustrated in FIGS. 5 to 7, the plurality of through-holes 25penetrates from the first surface 20 a, which is one side along a normaldirection N of the deposition mask 20, through the second surface 20 bwhich is the other side along the normal direction N of the depositionmask 20. In the illustrated example, a first concave portion 30 (or afirst opening 30) is formed by etching on the first surface 21 a of themetal plate 21, which is one side in the normal direction N of thedeposition mask 20, and a second concave portion 35 (or a second opening35) is formed on the second surface 21 b of the metal plate 21 which isthe other side in the normal direction N of the deposition mask 20 aswill be described in detail later. The first concave portion 30 isconnected to the second concave portion 35 so that the second concaveportion 35 and the first concave portion 30 communicate with each other.The through-hole 25 is formed of the second concave portion 35 and thefirst concave portion 30 connected to the second concave portion 35.

As illustrated in FIGS. 5 to 7, the opening area of each of the secondconcave portions 35 in a cross section along a plate plane of thedeposition mask 20 at each position along the normal direction N of thedeposition mask 20 gradually decreases from the second surface 20 b sideto the first surface 20 a side of the deposition mask 20. Similarly, theopening area of each of the first concave portions 30 in the crosssection along the plate plane of the deposition mask 20 at each positionalong the normal direction N of the deposition mask 20 graduallydecreases from the first surface 20 a side to the second surface 20 b ofthe deposition mask 20.

As illustrated in FIGS. 5 to 7, a wall surface 31 of the first concaveportion 30 and a wall surface 36 of the second concave portion 35 areconnected via a circumferential connecting portion 41. The connectingportion 41 is defined by a ridge of an overhang where the wall surface31 of the first concave portion 30 inclined with respect to the normaldirection N of the deposition mask 20 and the wall surface 36 of thesecond concave portion 35 inclined with respect to the normal directionN of the deposition mask 20 are joined. Further, the connecting portion41 defines a penetrating portion 42 where the opening area of thethrough-hole 25 is the minimum in a plan view of the deposition mask 20.

As illustrated in FIGS. 5 to 7, the two adjacent through-holes 25 arespaced apart from each other along the plate plane of the depositionmask 20 on a surface on the other side along the normal direction N ofthe deposition mask 20, that is, on the first surface 20 a of thedeposition mask 20. That is, when the first concave portion 30 isproduced by etching the metal plate 21 from the first surface 21 a sideof the metal plate 21 corresponding to the first surface 20 a of thedeposition mask 20 as in a manufacturing method to be described later,the first surface 21 a of the metal plate 21 remains between the twoadjacent first concave portion 30.

Similarly, the two adjacent second concave portions 35 may be alsospaced apart from each other along the plate plane of the depositionmask 20 on one side along the normal direction N of the deposition mask20, that is, on the second surface 20 b side of the deposition mask 20as illustrated in FIGS. 5 and 7. That is, the second surface 21 b of themetal plate 21 may remain between the two adjacent second concaveportions 35. In the following description, a portion of the effectiveregion 22 on the second surface 21 b of the metal plate 21 that remainswithout being etched is also referred to as a top portion 43. As thedeposition mask 20 is produced so as to leave such a top portion 43, itis possible to make the deposition mask 20 have sufficient strength. Asa result, it is possible to suppress the deposition mask 20 from beingdamaged during conveyance, for example. Incidentally, if a width β ofthe top portion 43 is too large, shadow is generated in the depositionstep so that the utilization efficiency of the deposition material 98may decrease. Therefore, it is preferable that the deposition mask 20 beproduced such that the width β of the top portion 43 does not becomeexcessively large. For example, the width β of the top portion 43 ispreferably 2 μm or less. Incidentally, the width β of the top portion 43generally varies depending on a direction in which the deposition mask20 is cut. For example, the widths 13 of the top portion 43 illustratedin FIGS. 5 and 7 may be different from each other. In this case, thedeposition mask 20 may be configured such that the width β of the topportion 43 becomes 2 μm or less even when the deposition mask 20 is cutin any direction.

Incidentally, etching may be performed such that two adjacent secondconcave portions 35 are connected depending on places as illustrated inFIG. 6. That is, a place where the second surface 21 b of the metalplate 21 does not remain may exist between the two adjacent secondconcave portions 35. In addition, etching may be performed such that thetwo adjacent second concave portions 35 are connected across the entiresecond surface 21 b although not illustrated.

When the deposition mask device 10 is accommodated in the depositiondevice 90 as illustrated in FIG. 1, the first surface 20 a of thedeposition mask 20 faces the organic EL substrate 92 as illustrated by atwo-dot chain line in FIG. 5, and the second surface 20 b of thedeposition mask 20 is positioned on a side of the crucible 94 holdingthe deposition material 98. Therefore, the deposition material 98 passesthrough the second concave portion 35 whose opening area graduallydecreases and adheres to the organic EL substrate 92. The depositionmaterial 98 not only moves along the normal direction N of the organicEL substrate 92 from the crucible 94 toward the organic EL substrate 92but also moves in a direction which is greatly inclined with respect tothe normal direction N of the organic EL substrate 92 as illustrated byan arrow directed from the second surface 20 b side to the first surface20 a in FIG. 5. At this time, when the thickness of the deposition mask20 is large, most of the deposition material 98 that obliquely movesreaches and adheres to the wall surface 36 of the second concave portion35 before reaching the organic EL substrate 92 through the through-hole25. Therefore, it is considered that it is preferable to reduce thethickness T0 of the deposition mask 20 so as to reduce the height of thewall surface 36 of the second concave portion 35 or the wall surface 31of the first concave portion 30 in order to enhance the utilizationefficiency of the deposition material 98. That is, it can be said thatit is preferable to use the metal plate 21 having the thickness, assmall as possible, within a range where the strength of the depositionmask 20 can be secured, as the metal plate 21 to form the depositionmask 20. In consideration of this point, the thickness T0 of thedeposition mask 20 is preferably set to 85 μm or less, for example, 5 μmto 85 μm in the present embodiment. Alternatively, the thickness T0 isset to 80 μm or less, for example, 10 μm to 80 μm, or 20 μm to 80 μm.The thickness T0 of the deposition mask 20 may be set to 40 μm or less,for example, 10 to 40 μm, or 20 to 40 μm in order to further improve theaccuracy of deposition. Incidentally, the thickness T0 is a thickness ofthe peripheral region 23, that is, a thickness of the portion of thedeposition mask 20 where the first concave portion 30 and the secondconcave portion 35 are not formed. Therefore, it can be said that thethickness T0 is the thickness of the metal plate 21.

In FIG. 5, a minimum angle of a straight line L1, which passes throughthe connecting portion 41, which is the portion having the minimumopening area of the through-hole 25, and another arbitrary position ofthe wall surface 36 of the second concave portion 35, with respect tothe normal direction N of the deposition mask 20 is indicated by areference sign θ1. That is, a path that forms the angle θ1 with respectto the normal direction N of the deposition mask 20 among paths of thedeposition material 98 passing through the end 38 of the through-hole 25(the second concave portion 35) on the second surface 20 b side of thedeposition mask 20, the paths that can reach the organic EL substrate 92is represented by a reference sign L1, which is similar to the caseillustrated in FIG. 21 to be described later. It is advantageous toincrease the angle 81 in order to allow the deposition material 98moving obliquely to reach the organic EL substrate 92 as much aspossible without reaching the wall surface 36. Upon increasing the angleθ1, it is also advantageous to not only reduce the thickness T0 of thedeposition mask 20 but also reduce the above-described width β of thetop portion 43.

In FIG. 7, a reference sign α represents a width of a portion(hereinafter also referred to as a rib portion) remaining without beingetched in the effective region 22 of the first surface 21 a of the metalplate 21. The width α of the rib portion and a dimension r₂ of thepenetrating portion 42 are appropriately determined according todimensions of the organic EL display device and the number of displaypixels. Table 1 illustrates exemplary values of the width α of the ribportion and the dimension r₂ of the penetrating portion 42 obtaineddepending on the number of display pixels, in a 5-inch organic ELdisplay device.

TABLE 1 DIMENSION OF NUMBER OF DISPLAY WIDTH OF RIB PENETRATING PIXELSPORTION PORTION FHD (Full High Definition) 20 μm 40 μm WQHD (Wide QuadHigh 15 μm 30 μm Definition) UHD (Ultra High Definition) 10 μm 20 μm

Although not limited, the deposition mask 20 according to the presentembodiment is particularly advantageous in the case of manufacturing anorganic EL display device having a pixel density of 450 ppi or more.Hereinafter, exemplary dimensions of the deposition mask 20 required tomanufacture such an organic EL display device having a high pixeldensity will be described with reference to FIG. 8. FIG. 8 is anenlarged cross-sectional view illustrating the through-hole 25 of thedeposition mask 20 illustrated in FIG. 5 and the vicinity thereof.

In FIG. 8, a distance from the first surface 20 a of the deposition mask20 to the connecting portion 41 in the direction along the normaldirection N of the deposition mask 20, that is, a height of the wallsurface 31 of the first concave portion 30 is represented by a referencesign r₁ as a parameter relating to a shape of the through-hole 25.Further, a dimension of the first concave portion 30 at a portion wherethe first concave portion 30 is connected to the second concave portion35, that is, a dimension of the penetrating portion 42 is represented bya reference sign r₂. In addition, an angle of a straight line L2, whichconnects the connecting portion 41 and a distal edge of the firstconcave portion 30 on the first surface 21 a of the metal plate 21, withrespect to the normal direction N of the metal plate 21 is representedby a reference sign 82 in FIG. 8.

In the case of manufacturing an organic EL display device having a pixeldensity of 450 ppi or more, the dimension r₂ of the penetrating portion42 is preferably set to 10 to 60 μm. As a result, it is possible toprovide the deposition mask 20 capable of manufacturing the organic ELdisplay device having a high pixel density. Preferably, the height r₁ ofthe wall surface 31 of the first concave portion 30 is set to 6 μm orless.

Next, the above-described angle 82 illustrated in FIG. 8 will bedescribed. The angle 82 corresponds to a maximum value of an inclinationangle of the deposition material 98 that can reach the organic ELsubstrate 92 among the deposition materials 98 inclined with respect tothe normal direction N of the metal plate 21 and flown to pass throughthe penetrating portion 42 in the vicinity of the connecting portion 41.This is because the deposition materials 98 that have passed through theconnecting portion 41 and flown with an inclination angle larger thanthe angle 82 adhere to the wall surface 31 of the first concave portion30 before reaching the organic EL substrate 92. Therefore, it ispossible to prevent the deposition material 98 that have flown with alarge inclination angle and passed through the penetrating portion 42from adhering to the organic EL substrate 92 by decreasing the angle 82,and accordingly, it is possible to prevent the deposition material 98from adhering to a portion outside a portion of the organic EL substrate92 overlapping with the penetrating portion 42. That is, the decrease ofthe angle θ2 leads to suppression of variations in the area andthickness of the deposition material adhering to the organic ELsubstrate 92. From this viewpoint, for example, the through-hole 25 isformed such that the angle 82 is 45 degrees or smaller. Incidentally,FIG. 8 illustrates an example in which a dimension of the first concaveportion 30 in the first surface 21 a, that is, an opening dimension ofthe through-hole 25 in the first surface 21 a is larger than a dimensionr2 of the first concave portion 30 in the connecting portion 41. Thatis, an example in which a value of the angle 82 is a positive value isillustrated. However, the dimension r2 of the first concave portion 30in the connecting portion 41 may be larger than the dimension of thefirst concave portion 30 in the first surface 21 a although notillustrated. That is, the value of the angle θ2 may be a negative value.

Next, a method of manufacturing the deposition mask 20 by the etchingprocess will be described.

(Method of Manufacturing Metal Plate)

First, a method of manufacturing a metal plate used to manufacture thedeposition mask will be described.

(Rolling Step) First, the base material 155 made of an iron alloycontaining nickel is prepared, and this base material 155 is conveyedtoward a rolling device 156 including a pair of rolling rolls 156 a and156 b along a direction indicated by an arrow as illustrated in FIG. 9.The base material 155 that has reached between the pair of the rollingrolls 156 a and 156 b is rolled by the pair of rolling rolls 156 a and156 b, and as a result, the base material 155 is reduced in thicknessand stretched along the conveying direction. As a result, a platematerial 164X having a thickness t₀ can be obtained. As illustrated inFIG. 9, a winding body 162 may be formed by winding the plate material164X around a core 161. A specific value of the thickness t₀ ispreferably 5 μm to 85 μm as described above.

Incidentally, FIG. 9 illustrates only an outline of the rolling step,and specific configuration and procedure for carrying out the rollingstep are not particularly limited. For example, the rolling step mayinclude a hot rolling step of processing a base material at atemperature equal to or higher than a temperature at which a crystalarray of an invar material forming the base material 155 is changed anda cold rolling step of processing a base material at a temperature equalto or lower than the temperature at which the crystal array of the invarmaterial is changed. In addition, a direction in which the base material155 or the plate material 164X passes between the pair of rolling rolls156 a and 156 b is not limited to one direction. For example, the basematerial 155 or the plate material 164X may be gradually rolled byrepeatedly causing the base material 155 or the plate material 164X topass between the pair of rolling rolls 156 a and 156 b in a directionfrom the left side to the right side of the paper plane and from theright side to the left side of the paper plane in FIGS. 9 and 10.

[Slitting Step]

Thereafter, a slitting step may be executed to cut off both ends of theplate material 164X obtained in the rolling step in the width directionover a predetermined range such that a width of the plate material 164Xfalls within a predetermined range. This slitting step is executed inorder to remove a crack that may occur at both the ends of the platematerial 164X due to rolling. As such a slitting step is executed, it ispossible to prevent a phenomenon that the plate material 164X breaks,that is, generation of a so-called plate breakage due to the crack as astarting point.

[Annealing Step]

Thereafter, the plate material 164X is annealed using an annealingdevice 157 in order to remove residual stress (internal stress)accumulated in the plate material 164X by rolling, thereby obtaining thelong metal plate 164 as illustrated in FIG. 10. As illustrated in FIG.10, the annealing step may be executed while pulling the plate material164X or the long metal plate 164 in the conveying direction(longitudinal direction). That is, the annealing step may be executednot as so-called batch-type annealing but as continuous annealing whileperforming conveyance.

Preferably, the annealing step is performed in a non-reducing atmosphereor an inert gas atmosphere. Here, the non-reducing atmosphere is anatmosphere not containing a reducing gas such as hydrogen. “Notcontaining a reducing gas” means that a concentration of the reducinggas such as hydrogen is 4% or less. The inert gas atmosphere is anatmosphere in which 90% or more of an inert gas such as an argon gas, ahelium gas, and a nitrogen gas is present. As the annealing step isexecuted in the non-reducing atmosphere or the inert gas atmosphere, itis possible to suppress generation of nickel hydroxide on the firstsurface 164 a or the second surface 164 b of the long metal plate 164.

Since the annealing step is executed, it is possible to obtain the longmetal plate 164 having the thickness t₀ from which residual strain hasbeen removed to some extent. The thickness t₀ is usually equal to thethickness T0 of the deposition mask 20.

The long metal plate 164 having the thickness t₀ may be produced byrepeating the above-described rolling step, slitting step, and annealingstep a plurality of times. In addition, FIG. 10 illustrates the examplein which the annealing step is performed while pulling the long metalplate 164 in the longitudinal direction, but it is not limited thereto,and the annealing step may be executed in a state where the long metalplate 164 is wound around the core 161. That is, the batch-typeannealing may be executed. In the case where the annealing step isexecuted in the state where the long metal plate 164 is wound around thecore 161, there is a case where the long metal plate 164 is subject towarpage according to a winding diameter of the winding body 162.Therefore, it is advantageous to execute the annealing step whilepulling the long metal plate 164 in the longitudinal direction dependingon a winding diameter of the winding body or and a material forming thebase material 155 of the winding body 162.

[Cutting Step]

Thereafter, each of both ends of the long metal plate 164 in the widthdirection is cut off over a predetermined range, thereby performing acutting step of adjusting a width of the long metal plate 164 to adesired width. In this manner, the long metal plate 164 having a desiredthickness and width can be obtained.

(Method of Manufacturing Deposition Mask) Next, a method ofmanufacturing the deposition mask 20 using the long metal plate 164 willbe described mainly with reference to FIGS. 11 to 19. In the method ofmanufacturing the deposition mask 20 to be described hereinafter, thelong metal plate 164 is supplied, the through-hole 25 is formed in thelong metal plate 164, and the long metal plate 164 is cut, therebyobtaining the deposition mask 20 made of the sheet-like metal plate 21as illustrated in FIG. 11.

More specifically, the method of manufacturing the deposition mask 20include: a step of supplying the long metal plate 164 extending in aband shape; a step of performing etching on the long metal plate 164using a photolithography technique to form the first concave portion 30from the first surface 164 a side in the long metal plate 164, and astep of performing etching on the long metal plate 164 using aphotolithography technique to form the second concave portion 35 in thelong metal plate 164 from the second surface 164 b side. Further, thefirst concave portion 30 and the second concave portion 35 formed in thelong metal plate 164 communicate with each other, thereby producing thethrough-hole 25 in the long metal plate 164. In the examples illustratedin FIGS. 12 to 19, the step of forming the first concave portion 30 isperformed before the step of forming the second concave portion 35, anda step of sealing the produced first concave portion 30 is furtherprovided between the step of forming the first concave portion 30 andthe step of forming the second concave portion 35. Details of each stepwill be described hereinafter.

In FIG. 11, a manufacturing device 160 configured to produce thedeposition mask 20 is illustrated. First, a winding body 162 obtained bywinding the long metal plate 164 around the core 161 is prepared asillustrated in FIG. 11. Then, as the core 161 rotates and the windingbody 162 is unwound, the long metal plate 164 extending in the bandshape is supplied as illustrated in FIG. 11. Incidentally, the longmetal plate 164 is formed with the through-hole 25 to form thesheet-like metal plate 21, and further, the deposition mask 20.

The supplied long metal plate 164 is conveyed to an etching device(etching means) 170 by a conveying roller 172. Each process illustratedin FIGS. 12 to 19 is performed by the etching means 170. Incidentally,it is assumed that the plurality of deposition masks 20 is allocated inthe width direction of the long metal plate 164 in the presentembodiment. That is, the plurality of deposition masks 20 is producedfrom regions occupying predetermined positions of the long metal plate164 in the longitudinal direction. In this case, the plurality ofdeposition masks 20 is allocated to the long metal plate 164 preferablysuch that the longitudinal direction of the deposition mask 20 coincideswith a rolling direction of the long metal plate 164.

First, resist films 165 c and 165 d containing a negative photosensitiveresist material are formed on the first surface 164 a and the secondsurface 164 b of the long metal plate 164 as illustrated in FIG. 12. Amethod of pasting a film formed with a layer containing a photosensitiveresist material such as an acrylic photocurable resin, that is, aso-called dry film on the first surface 164 a and the second surface 164b of the long metal plate 164 is adopted as a method of forming theresist films 165 c and 165 d.

Next, exposure masks 168 a and 168 b which allow light to pass throughregions that are desirably removed in the resist films 165 c and 165 dare prepared, and the exposure masks 168 a and 168 b are arranged on theresist films 165 c and 165 d, respectively, as illustrated in FIG. 13.For example, a glass dry plate which does not allow light to passthrough the regions that are desirably removed in the resist films 165 cand 165 d is used as the exposure masks 168 a and 168 b. Thereafter, theexposure masks 168 a and 168 b are sufficiently brought into closecontact with the resist films 165 c and 165 d by vacuum adhesion.Incidentally, a positive material may be used as photosensitive resistmaterial. In this case, an exposure mask configured to allow light topass through a region that is desirably removed out of the resist filmis used as the exposure mask.

Thereafter, the resist films 165 c and 165 d are exposed to lightthrough the exposure masks 168 a and 168 b (an exposure step). Further,the resist films 165 c and 165 d are developed to form images on theexposed resist films 165 c and 165 d (a developing step). As describedabove, it is possible to form the first resist pattern 165 a on thefirst surface 164 a of the long metal plate 164 and the second resistpattern 165 b on the second surface 164 b of the long metal plate 164 asillustrated in FIG. 14. Incidentally, the developing step may include aresist heat treatment step for enhancing each hardness of the resistfilms 165 c and 165 d or more strongly bringing the resist films 165 cand 165 d to be close contact with the long metal plate 164. The resistheat treatment step is executed in an atmosphere of an inert gas such asan argon gas, a helium gas, and a nitrogen gas at, for example, 100° C.to 400° C.

Next, a first surface etching step of etching a region of the firstsurface 164 a of the long metal plate 164 that is not covered with thefirst resist pattern 165 a by using a first etching solution isperformed as illustrated in FIG. 15. For example, the first etchingsolution is sprayed from a nozzle arranged on a side opposing the firstsurface 164 a of the conveyed long metal plate 164 toward the firstsurface 164 a of the long metal plate 164 through the first resistpattern 165 a. As a result, erosion by the first etching solutionproceeds in the region of the long metal plate 164 that is not coveredwith the first resist pattern 165 a as illustrated in FIG. 15. As aresult, a large number of the first concave portions 30 are formed inthe first surface 164 a of the long metal plate 164. For example, asolution containing a ferric chloride solution and hydrochloric acid isused as the first etching solution.

Thereafter, the first concave portion 30 is covered with a resin 169having resistance against a second etching solution to be used in asubsequent second surface etching step as illustrated in FIG. 16. Thatis, the first concave portion 30 is sealed by the resin 169 havingresistance against the second etching solution. In the exampleillustrated in FIG. 16, a film of the resin 169 is formed so as to covernot only the formed first concave portion 30 but also the first surface164 a (the first resist pattern 165 a).

Next, the second surface etching step of etching a region of the secondsurface 164 b of the long metal plate 164 that is not covered with thesecond resist pattern 165 b to form the second concave portion 35 on thesecond surface 164 b is performed as illustrated in FIG. 17. The secondsurface etching step is performed until the first concave portion 30 andthe second concave portion 35 communicate with each other to form thethrough-hole 25. For example, a solution containing a ferric chloridesolution and hydrochloric acid is used as the second etching solution,which is similar to the above-described first etching solution.

Incidentally, the erosion by the second etching solution is performed ina portion of the long metal plate 164 which is in contact with thesecond etching solution. Therefore, the erosion proceeds not only in thenormal direction N (thickness direction) of the long metal plate 164 butalso in the direction along the plate plane of the long metal plate 164.Here, the second surface etching step is preferably ended before the twosecond concave portions 35 respectively formed at positions opposing twoadjacent holes 166 a of the second resist pattern 165 b join each otheron the back side of a bridge portion 167 a positioned between the twoholes 166 a. As a result, the above-described top portion 43 can be lefton the second surface 164 b of the long metal plate 164 as illustratedin FIG. 18.

Thereafter, the resin 169 is removed from the long metal plate 164 asillustrated in FIG. 19. The resin 169 can be removed, for example, byusing an alkali-based peeling solution.

When the alkali-based peeling solution is used, the resist patterns 165a and 165 b can also be removed simultaneously with the resin 169 asillustrated in FIG. 19. Incidentally, the resist patterns 165 a and 165b may be removed separately from the resin 169 by using a peelingsolution different from the peeling solution for peeling the resin 169after removing the resin 169.

The long metal plate 164 having a large number of the through-holes 25formed in this manner is conveyed to a cutting device (cutting means)173 by conveying rollers 172 and 172 rotating while holding the longmetal plate 164. Incidentally, the above-described supplied core 161 isrotated via a tension (tensile stress) acting on the long metal plate164 due to the rotation of the conveying rollers 172 and 172, and thelong metal plate 164 is supplied from the winding body 162.

Thereafter, the long metal plate 164 having a large number of thethrough-holes 25 formed therein is cut into predetermined length andwidth by the cutting device (cutting means) 173, thereby obtaining thesheet-like metal plate 21 having a large number of the through-holes 25formed therein, that is, the deposition mask 20.

(Deposition Mask Manufactured by Plating Process)

Incidentally, the deposition mask 20 can also be manufactured by using aplating process. Therefore, the deposition mask 20 manufactured by theplating process will be described hereinafter. First, shapes of thethrough-hole 25 and a peripheral part thereof when the deposition mask20 is formed by the plating process will be described.

FIG. 20 is an enlarged plan view illustrating the effective region 22from the second surface 20 b side of the deposition mask 20 manufacturedby the plating process. As illustrated in FIG. 4, the plurality ofthrough-holes 25 formed in each of the effective regions 22 are arrayedat predetermined pitches along the two directions orthogonal to eachother in the effective region 22 in the illustrated example. An exampleof the through-hole 25 will be described in more detail mainly withreference to FIG. 21. FIG. 21 is a cross-sectional view of the effectiveregion 22 in FIG. 20 as viewed from the A-A direction.

As illustrated in FIG. 21, the deposition mask 20 includes a first metallayer 32 forming the first surface 20 a, a second metal layer 37provided on the first metal layer 32 and forming the second surface 20b. When the deposition material 98 is deposited on the organic ELsubstrate 92 (during deposition), the second metal layer 37 is arrangedon the side of the above-described frame 15 (see FIG. 1 and the like).The first metal layer 32 is provided with the first opening 30 in apredetermined pattern, and the second metal layer 37 is provided withthe second opening 35 in a predetermined pattern. The first opening 30and the second opening 35 communicate with each other to form thethrough-hole 25 extending from the first surface 20 a to the secondsurface 20 b of the deposition mask 20.

As illustrated in FIG. 20, the first opening 30 and the second opening35 forming the through-hole 25 may have a substantially polygonal shapein a plan view. Here, an example in which the first opening 30 and thesecond opening 35 are formed in a substantially quadrangular shape, morespecifically, a substantially square shape is illustrated. Although notillustrated, the first opening 30 and the second opening 35 may haveother substantially polygonal shapes such as a substantially hexagonalshape and a substantially octagonal shape. Incidentally, the“substantially polygonal shape” is a concept including a shape in whichcorners of a polygon are rounded. Although not illustrated, the firstopening 30 and the second opening 35 may have a circular shape. Inaddition, a shape of the first opening 30 and a shape of the secondopening 35 are not necessarily formed in similar shapes as long as thesecond opening 35 has the outline that surrounds the first opening 30 ina plan view.

In FIG. 21, the reference sign 41 represents the connecting portion atwhich the first metal layer 32 and the second metal layer 37 areconnected. In addition, the reference sign S0 represents a dimension ofthe through-hole 25 in the connecting portion 41 between the first metallayer 32 and the second metal layer 37. Incidentally, FIG. 21illustrates an example in which the first metal layer 32 and the secondmetal layer 37 are in contact with each other, but it is not limitedthereto, and another layer may be interposed between the first metallayer 32 and the second metal layer 37. For example, a catalyst layer,configured to promote precipitation of the second metal layer 37 on thefirst metal layer 32, may be provided between the first metal layer 32and the second metal layer 37.

FIG. 22 is a view illustrating each part of the first metal layer 32 andthe second metal layer 37 of FIG. 21 in an enlarged manner. Asillustrated in FIG. 22, a width M2 of the second metal layer 37 on thesecond surface 20 b of the deposition mask 20 is smaller than a width M1of the first metal layer 32 on the first surface 20 a of the depositionmask 20. In other words, the opening dimension S2 of the through-hole 25(the second opening 35) on the second surface 20 b is larger than theopening dimension S1 of the through-hole 25 (the first opening 30) onthe first surface 20 a. Hereinafter, advantages obtained by forming thefirst metal layer 32 and the second metal layer 37 in this manner willbe described.

The deposition material 98 flying from the second surface 20 b side ofthe deposition mask 20 sequentially passes through the second opening 35and the first opening 30 of the through-hole 25 and adheres to theorganic EL substrate 92. A region of the organic EL substrate 92 towhich the deposition material 98 adheres is mainly determined by theopening dimension S1 and an opening shape of the through-hole 25 on thefirst surface 20 a. Meanwhile, the deposition material 98 not only movesalong a normal direction N of the deposition mask 20 from the crucible94 toward the organic EL substrate 92 but also moves in a directionwhich is greatly inclined with respect to the normal direction N of thedeposition mask 20 as illustrated by an arrow L1 directed from thesecond surface 20 b side to the first surface 20 a in FIGS. 21 and 22.Here, if the opening dimension S2 of the through-hole 25 on the secondsurface 20 b is the same as the opening dimension S1 of the through-hole25 on the first surface 20 a, most of the deposition material 98 movingin the direction that is greatly inclined with respect to the normaldirection N of the deposition mask 20 adheres to the second surface 20 bof the deposition mask 20 (upper surface of the second metal layer 37 inFIG. 21) and reaches and adheres to the wall surface 36 of the secondopening 35 of the through-hole 25 before passing through thethrough-hole 25 and reaching the organic EL substrate 92. Thus, theamount of the deposition material 98 that hardly passes through thethrough-hole 25 increases. Therefore, it can be said that it ispreferable to increase the opening dimension S2 of the second opening35, that is, to reduce the width M2 of the second metal layer 37 inorder to enhance the utilization efficiency of the deposition material98.

In FIG. 21, a minimum angle formed by the straight line L1 in contactwith the wall surface 36 of the second metal layer 37 and the wallsurface 31 of the first metal layer 32 with respect to the normaldirection N of the deposition mask 20 is represented by a reference signθ1. It is advantageous to increase the angle θ1 in order to allow thedeposition material 98 moving obliquely to reach the organic ELsubstrate 92 as much as possible. For example, it is preferable to setthe angle θ1 at 45° or larger.

Upon increasing the angle 81, it is advantageous to set the width M2 ofthe second metal layer 37 to be smaller than the width M1 of the firstmetal layer 32. As apparent from the drawing, it is advantageous toreduce a thickness T1 of the first metal layer 32 and a thickness T2 ofthe second metal layer 37 upon increasing the angle 81. Incidentally, itis considered that the strength of the deposition mask 20 decreases whenthe width M2 of the second metal layer 37, the thickness T1 of the firstmetal layer 32, and the thickness T2 of the second metal layer 37 areexcessively reduced, and thus, the deposition mask 20 is damaged duringconveyance or use. For example, it is considered that the depositionmask 20 is damaged by tensile stress applied to the deposition mask 20when the deposition mask 20 is stretched to be installed to the frame15. When considering these points, it can be said that it is preferableto set dimensions of the first metal layer 32 and the second metal layer37 within the following ranges. As a result, the above-described angle81 can be set to, for example, 45° or larger.

-   -   The width M1 of the first metal layer 32: 5 μm to 25 μm    -   The width M2 of the second metal layer 37: 2 μm to 20 μm    -   The thickness T0 of the deposition mask 20: 3 μm to 50 μm, more        preferably 3 μm to 50 μm, still more preferably 3 μm to 30 μm,        and even still more preferably 3 μm to 25 μm    -   The thickness T1 of the first metal layer 32: 5 μm or less    -   The thickness T2 of the second metal layer 37: 2 μm to 50 μm,        more preferably 3 μm to 50 μm, still more preferably 3 μm to 30        μm, and even still more preferably 3 μm to 25 μm

In the present embodiment, the thickness T0 of the deposition mask 20 isthe same in the effective region 22 and the peripheral region 23.

The above opening dimensions S0, S1, and S2 are appropriately set inconsideration of the pixel density of the organic EL display device,desired values of the above angle θ1, and the like. For example, in thecase of manufacturing an organic EL display device having a pixeldensity of 400 ppi or more, the opening dimension S0 of the through-hole25 in the connecting portion 41 can be set to 15 μm to 60 μm. Inaddition, the opening dimension S1 of the first opening 30 on the firstsurface 20 a is set to 10 μm to 50 μm, and the opening dimension S2 ofthe second opening 35 on the second surface 20 b is set to 15 μm to 60μm.

As illustrated in FIG. 22, a recessed portion 34 may be formed on thefirst surface 20 a of the deposition mask 20 formed of the first metallayer 32. The recessed portion 34 is formed so as to correspond to aconductive pattern 52 of a pattern substrate 50 to be described laterwhen manufacturing the deposition mask 20 by the plating process. Adepth D of the recessed portion 34 is, for example, 50 nm to 500 nm.Preferably, an outer edge 34 e of the recessed portion 34 formed in thefirst metal layer 32 is positioned between the end 33 of the first metallayer 32 and the connecting portion 41.

Next, an example of manufacturing the deposition mask 20 by the platingprocess will be described.

(Method of Manufacturing Deposition Mask)

FIGS. 23 to 26 are views for describing the method of manufacturing thedeposition mask 20.

[Pattern Substrate Preparation Step]

First, the pattern substrate 50 illustrated in FIG. 23 is prepared. Thepattern substrate 50 has a base material 51 having insulating propertiesand a conductive pattern 52 formed on the base material 51. Theconductive pattern 52 has a pattern corresponding to the first metallayer 32. Incidentally, the pattern substrate 50 may be subjected to areleasing process in order to facilitate a separation step, which willbe described later, of separating the deposition mask 20 from thepattern substrate 50.

[First Plating Process Step]

Next, a first plating process step of supplying a first plating solutiononto the base material 51 on which the conductive pattern 52 has beenformed to precipitate the first metal layer 32 on the conductive pattern52 is performed. For example, the base material 51 on which theconductive pattern 52 has been formed is immersed in a plating tankfilled with the first plating solution. As a result, the first metallayer 32 provided with the first openings 30 in the predeterminedpattern can be obtained on the pattern substrate 50 as illustrated inFIG. 24.

Incidentally, the first metal layer 32 can be formed not only in aportion overlapping with the conductive pattern 52 when viewed along thenormal direction of the base material 51 but also in a portion that doesnot overlap with the conductive pattern 52 as illustrated in FIG. 24 interms of characteristics of the plating process. This is because thefirst metal layer 32 is further precipitated on the surface of the firstmetal layer 32 which has been precipitated on the portion overlappingwith an end 54 of the conductive pattern 52. As a result, the end 33 ofthe first opening 30 can be positioned in a portion that does notoverlap with the conductive pattern 52 when viewed along the normaldirection of the base material 51 as illustrated in FIG. 24. Inaddition, the above recessed portion 34 corresponding to the thicknessof the conductive pattern 52 is formed on a surface of the first metallayer 32 on the side in contact with the conductive pattern 52.

A specific method of the first plating process step is not particularlylimited as long as the first metal layer 32 can be precipitated on theconductive pattern 52 For example, the first plating process step may beperformed as a so-called electrolytic plating process step of causing anelectric current to flow through the conductive pattern 52 toprecipitate the first metal layer 32 on the conductive pattern 52.Alternatively, the first plating process step may be an electrolessplating process step.

Components of the first plating solution to be used are appropriatelydetermined depending on characteristics required for the first metallayer 32. For example, when the first metal layer 32 is made of an ironalloy containing nickel, a mixed solution of a solution containing anickel compound and a solution containing an iron compound can be usedas the first plating solution. For example, a mixed solution of asolution containing nickel sulfamate or nickel bromide and a solutioncontaining ferrous sulfamate can be used. The plating solution maycontain various additives. As the additives, a pH buffer such as boricacid, a primary brightener such as saccharin sodium, a secondarybrightener such as butynediol, propargyl alcohol, coumarin, formalin,and thiourea, an antioxidant, a stress relaxation agent, and the likecan be used. Among them, the primary brightener may contain a sulfurcomponent.

[Resist Formation Step]

Next, a resist formation step is performed on the base material 51 andthe first metal layer 32 to form a resist pattern 55 with apredetermined gap 56 therebetween. As illustrated in FIG. 25, the resistformation step is performed such that the first opening 30 of the firstmetal layer 32 is covered with the resist pattern 55 and the gap 56 ofthe resist pattern 55 is positioned on the first metal layer 32.

[Second Plating Process Step]

Next, a second plating process step of supplying a second platingsolution to the gap 56 of the resist pattern 55 to precipitate thesecond metal layer 37 on the first metal layer 32 is performed. Forexample, the base material 51 on which the first metal layer 32 has beenformed is immersed in a plating tank filled with the second platingsolution. As a result, the second metal layer 37 can be formed on thefirst metal layer 32 as illustrated in FIG. 26.

A specific method of the second plating process step is not particularlylimited as long as the second metal layer 37 can be precipitated on thefirst metal layer 32. For example, the second plating process step maybe performed as a so-called electrolytic plating process step of causingan electric current to flow through the first metal layer 32 toprecipitate the second metal layer 37 on the first metal layer 32.Alternatively, the second plating process step may be an electrolessplating process step.

A plating solution which is the same as the above-described firstplating solution may be used as the second plating solution.Alternatively, a plating solution different from the first platingsolution may be used as the second plating solution. When thecomposition of the first plating solution and the composition of thesecond plating solution are the same, the composition of metal formingthe first metal layer 32 and the composition of metal forming the secondmetal layer 37 also become the same.

[Resist Removal Step]

Thereafter, a resist removal step of removing the resist pattern 55 isperformed. For example, the resist pattern 55 can be peeled off from thebase material 51, the first metal layer 32, and the second metal layer37 by using an alkali-based peeling solution.

[Separation Step]

Next, the separation step of separating a combined body of the firstmetal layer 32 and the second metal layer 37 from the base material 51is performed. Since an organic film formed by the above-describedreleasing process has been formed on the conductive pattern 52 when thecombined body is separated from the base material 51, the first metallayer 32 of the combined body is peeled off from a surface of theorganic film, and the conductive pattern 52 remains on the base material51 together with the organic film. As a result, it is possible to obtainthe deposition mask 20 that includes the first metal layer 32 providedwith the first openings 30 in the predetermined pattern and the secondmetal layer 37 provided with the second openings 35 communicating withthe first openings 30.

In the above description, the example in which the deposition mask 20formed by the plating process is constituted by the first metal layer 32and the second metal layer 37 has been described. However, it is notlimited thereto, and the deposition mask 20 formed by the platingprocess may be constituted by a single metal layer (not illustrated).

[Method of Manufacturing Deposition Mask Device]

Next, a method of manufacturing the deposition mask device 10 using thedeposition mask 20 obtained as above will be described.

First, a welding process of welding the deposition mask 20 prepared asdescribed above to the frame 15 by the etching process or the platingprocess is performed. As a result, it is possible to obtain thedeposition mask device 10 including the deposition mask 20 and the frame15. The deposition mask 20 thus obtained is welded to the frame 15 in astretched state, thereby obtaining the deposition mask device 10 asillustrated in FIG. 3.

(Deposition Mask Package)

Next, a description will be given regarding a deposition mask packagepackaging the deposition mask 20 obtained by the etching process or theplating process with reference to FIGS. 27 to 41.

As illustrated in FIGS. 27 to 29, a deposition mask package 60 accordingto the present embodiment includes a receiving portion 61, a lid portion62 provided above the receiving portion 61 and face the receivingportion 61, and a deposition mask stacked body 80 arranged between thereceiving portion 61 and the lid portion 62. Among them, the depositionmask stacked body 80 includes the deposition masks 20 described aboveand a plurality of interposed sheets 81 stacked on the deposition mask20. Details of the deposition mask stacked body 80 will be describedlater.

The deposition mask stacked body 80 is sandwiched between the receivingportion 61 and the lid portion 62. In the present embodiment, thereceiving portion 61 and the lid portion 62 are bound together byelastic belts 63 (binding means), and the receiving portion 61 and thelid portion 62 press and sandwich the deposition mask stacked body 80 bythe elastic forces of the elastic belts 63. Although an example in whichthe receiving portion 61 and the lid portion 62 are bound by the twoelastic belts 63 is illustrated here, but the number of the elasticbelts 63 is arbitrary as long as it is possible to prevent the receivingportion 61 and the lid portion 62 from being displaced from each otherduring transportation. In addition, it is not limited to the use of theelastic belt 63 as long as the receiving portion 61 and the lid portion62 can sandwich the deposition mask stacked body 80.

In the present embodiment, the receiving portion 61 and the lid portion62 are connected via a hinge portion 64. That is, the receiving portion61 and the lid portion 62 can be folded via the hinge portion 64, andcan be shifted from a developed state illustrated in FIG. 30 to a foldedstate illustrated in FIGS. 27 to 29. The receiving portion 61 and thelid portion 62 can return to the developed state after unpacking.

The receiving portion 61, the lid portion 62, and the hinge portion 64are integrally formed to constitute a double-hinged packaging member 65.FIG. 30 illustrates a traverse cross section of this packaging member65. Here, a longitudinal cross section means a cross section in thelongitudinal direction (first direction) of the deposition mask 20 to bepackaged. The traverse cross section means a cross section in the widthdirection (second direction) orthogonal to the longitudinal direction ofthe deposition mask 20 to be packaged.

As illustrated in FIG. 30, a V-shaped receiving-portion-side groove 66is formed between the receiving portion 61 and the hinge portion 64. AV-shaped lid-portion-side groove 67 is formed between the hinge portion64 and the lid portion 62. When the packaging member 65 is folded intothe state illustrated in FIGS. 27 to 29, these grooves 66 and 67 arecrushed. That is, a pair of groove wall surfaces defining the grooves 66and 67 abut on each other so that the packaging member 65 is foldable.When the receiving-portion-side groove 66 and the lid-portion-sidegroove 67 have an apex angle of 90°, it is possible to make thereceiving portion 61 and the lid portion 62 face each othersubstantially in the folded state of the packaging member 65. Anarbitrary material can be used for the packaging member 65 as long asthe plastic deformation of the deposition mask 20 during transportationcan be prevented. For example, a cardboard made of plastic can besuitably used from the viewpoints of strength and mass.

As illustrated in FIGS. 28 to 32, the receiving portion 61 has a flatfirst opposing surface 68 facing the lid portion 62 and a concaveportion 69 provided in the first opposing surface 68. When the receivingportion 61 has a configuration in which a plurality of material sheets(for example, plastic cardboard sheets) is stacked, an opening may beprovided in a sheet on the side of the first opposing surface 68, and noopening may be provided in a sheet on the opposite side of the firstopposing surface 68. In this case, it is possible to obtain the concaveportion 69 formed on the first opposing surface 68 when viewed as thereceiving portion 61. Here, the plastic cardboard sheet includes a pairof liners and a middle core having a corrugated cross section interposedbetween the liners. In the case of stacking the plurality of cardboardsheets, it is preferable to stack the plurality of cardboard sheets suchthat extending directions of corrugated ridges (or valleys) of middlecores of cardboard sheets, adjacent to each other, are perpendicular toeach other. In this case, it is possible to improve the strength of thereceiving portion 61 constituted by the stacked cardboard sheets.

As illustrated in FIG. 33, the concave portion 69 is formed in arectangular shape so as to have a longitudinal direction when viewedalong a stacking direction of the deposition mask 20 (normal direction Nof the deposition mask 20). The longitudinal direction of the concaveportion 69 extends along the longitudinal direction (first direction) ofthe deposition mask 20. In other words, the deposition mask 20 is placedon the concave portion 69 so as to have the longitudinal direction alongthe longitudinal direction of the concave portion 69.

A dimension D1 of the concave portion 69 in the longitudinal directionis larger than a dimension D2 from one end to the other end of theplurality of effective regions 22 in the longitudinal direction of thedeposition mask 20. As a result, all the effective region 22 of thedeposition mask 20 are arranged on the concave portion 69. However, thedimension D1 of the concave portion 69 in the longitudinal direction issmaller than the overall length (dimension in the longitudinaldirection) D3 of the deposition mask 20 in the longitudinal direction.As a result, ends 20 e on both sides of the deposition mask 20 in thelongitudinal direction are arranged not on the concave portion 69 but onthe first opposing surface 68, and are sandwiched between the receivingportion 61 and the lid portion 62. Thus, the deposition mask 20 isprevented from being displaced in the traverse direction between thereceiving portion 61 and the lid portion 62.

A dimension W1 of the concave portion 69 in the width direction of thedeposition mask 20 is larger than a dimension W2 of the deposition mask20 in the width direction. In this case, side edges 20 f on both sidesof the deposition mask 20 in the width direction are arranged on theconcave portion 69 in the vicinity of the effective region 22 of thedeposition mask 20. As a result, it is possible to effectively deflectthe effective region 22 of the deposition mask 20, which has received adownward force, inside the concave portion 69. Therefore, the plasticdeformation of the effective region 22 can be effectively prevented.

As illustrated in FIGS. 31 to 33, the concave portion 69 is covered witha first flexible film 70 having flexibility. It is preferable that thefirst flexible film 70 have flexibility enough to absorb a force appliedto the deposition mask 20 in the packaged state and an impact appliedduring transportation. In addition, it is preferable that the firstflexible film 70 has strength to such an extent to support thedeposition mask stacked body 80 (described later) including thedeposition mask 20. An arbitrary film material having an arbitrarythickness can be used for the first flexible film 70 as long as the filmhas the above characteristics. For example, a polyethylene terephthalate(PET) film having a thickness of 0.15 to 0.20 mm can be suitably used.Since the PET film is relatively hard and hardly forms wrinkles, theplastic deformation of the deposition mask 20 can be effectivelyprevented.

The first flexible film 70 is preferably antistatic-coated in order toprevent generation of static electricity. More specifically, the firstflexible film 70 may be coated with an antistatic agent, and anantistatic layer may be formed on both sides of the first flexible film70. In this case, it is possible to prevent the first flexible film 70from being charged, and it is possible to prevent the deposition mask 20and the interposed sheet 81 from adhering to each other due toelectrostatic action during unpacking. An example of the first flexiblefilm 70 is a polyester synthetic paper K2323-188-690 mm manufactured byToyobo Co., Ltd. sold under the trade name Crisper (registeredtrademark).

The first flexible film 70 is pasted to the first opposing surface 68 ofthe receiving portion 61 using an adhesive tape. More specifically, adimension D4 of the first flexible film 70 in the longitudinal directionof the deposition mask 20 is larger than the dimension D1 of the concaveportion 69 in the longitudinal direction as illustrated in FIG. 33. Inaddition, a dimension W3 of the first flexible film 70 in the widthdirection of the deposition mask 20 is larger than the dimension W1 ofthe concave portion 69 in the width direction. It is preferable that aperipheral portion of the first flexible film 70 be continuously pastedto the first opposing surface 68 over the entire circumference. As aresult, it is possible to effectively exhibit the flexibility of thefirst flexible film 70 when a downward force is applied to thedeposition mask 20, and the plastic deformation of the deposition mask20 supported by the first flexible film 70 can be further prevented. Anarbitrary material can be used as the adhesive tape as long as the firstflexible film 70 can be favorably attached to the receiving portion 61,and examples thereof can include a double-sided tap 665 manufactured by3M sold under the trade name Scotch (registered trademark).Incidentally, the first flexible film 70 may be pasted to the firstopposing surface 68 of the receiving portion 61 with an adhesive appliedthereto.

As illustrated in FIGS. 28 to 32, the lid portion 62 has a flat secondopposing surface 71 facing the receiving portion 61. In the presentembodiment, the second opposing surface 71 is not provided with aconcave portion like the first opposing surface 68. That is, the secondopposing surface 71 of the lid portion 62 is formed in a flat shape as awhole. As a result, it is possible to secure the strength of the lidportion 62. A portion of the first opposing surface 68 corresponding tothe deposition mask stacked body 80 is covered with a second flexiblefilm 72. As the second flexible film 72, a film material having the samethickness as the first flexible film 70 can be suitably used, and thesecond flexible film 72 can be attached to the second opposing surface71 of the lid portion 62 similarly to the first flexible film 70. Whenthe lid portion 62 is made of a plastic cardboard sheet, a corrugatedshape of a middle core of the cardboard sheet can be prevented frombeing transferred to the deposition mask 20 by the second flexible film72. In addition, it is possible to prevent the second opposing surface71 of the lid portion 62 from being scratched by using the secondflexible film 72.

As illustrated in FIGS. 28 and 29, the deposition mask stacked body 80in which the plurality of deposition masks 20 is stacked is interposedbetween the first flexible film 70 and the second flexible film 72. Thatis, the deposition mask stacked body 80 is sandwiched between thereceiving portion 61 and the lid portion 62 with each of the firstflexible film 70 and the second flexible film 72 interposedtherebetween.

As illustrated in FIGS. 31 and 32, the deposition mask stacked body 80includes the plurality of deposition masks 20 stacked on each other andthe plurality of interposed sheets 81 stacked on the first surface 20 aand the second surface 20 b of the deposition masks 20. In the presentembodiment, the plurality of deposition masks 20 and the plurality ofinterposed sheets 81 are alternately stacked, the first surface 20 a ofeach of the deposition masks 20 is covered with the interposed sheet 81facing the first surface 20 a, and the second surface 20 b is coveredwith the interposed sheet 81 facing the second surface 20 b. Inaddition, the interposed sheet 81 forms the lowermost stage and theuppermost stage of the deposition mask stacked body 80. That is, theinterposed sheet 81 is interposed between the deposition mask 20arranged at the lowermost position and the receiving portion 61, and theinterposed sheet 81 is interposed between the deposition mask 20arranged at the uppermost position and the lid portion 62.

The interposed sheet 81 is configured to prevent the through-holes 25 ofone deposition mask 20 and the through-holes 25 of the other depositionmask 20, which are adjacent to each other, from being caught by eachother. Therefore, both surfaces (surfaces facing the deposition mask 20or the flexible films 70, 72) of the interposed sheet 81 are formed in aflat shape, holes, irregularities, and the like are not formed in theinterposed sheet 81. The interposed sheet 81 prevents the plasticdeformation of the deposition mask 20 when taking out the individualdeposition masks 20 from the deposition mask stacked body 80.

The deposition mask 20 and the interposed sheet 81 constituting thedeposition mask stacked body 80 are not joined to the receiving portion61 and are not joined to the lid portion 62.

It is preferable that the deposition masks 20 in the deposition maskstacked body 80 have the same shape and the effective regions 22 of thedeposition masks 20 be arranged so as to overlap with each other whenviewed along the stacking direction, but it is not limited thereto. Inthe stacked state, for example, the number or shapes of the effectiveregions 22 of the deposition masks 20 may be different as long as allthe effective regions 22 of the deposition masks 20 can be arranged onthe concave portions 69.

An arbitrary material can be used for the interposed sheet 81 as long asthe plastic deformation of the deposition mask 20 can be prevented, butit is preferable that a difference between a thermal expansioncoefficient of the deposition mask 20 and a thermal expansioncoefficient of the interposed sheet 81 is within a predetermined range.In the present embodiment, the difference (absolute value) between thethermal expansion coefficient of the deposition mask 20 and the thermalexpansion coefficient of the interposed sheet 81 is 7 ppm/° C. or less.As a result, the difference between the thermal expansion coefficient ofthe deposition mask 20 and the thermal expansion coefficient of theinterposed sheet 81 is reduced.

When the deposition mask 20 is made of an iron alloy containing nickelin an amount of 30% by mass to 54% by mass, the interposed sheet 81 ispreferably made of an iron alloy containing nickel in an amount of 30%by mass to 54% by mass. For example, when the deposition mask 20 is madeof an invar material containing nickel in an amount of 34% by mass to38% by mass, the interposed sheet 81 is also preferably made of suchinvar material. In this case, the difference between the thermalexpansion coefficient of the deposition mask 20 and the thermalexpansion coefficient of the interposed sheet 81 can be reduced. In thecase where the deposition mask 20 is made of an iron alloy containingchromium such as stainless steel with good availability, the interposedsheet 81 is also preferably made of such an iron alloy containingchromium. Even in this case, the difference between the thermalexpansion coefficient of the deposition mask 20 and the thermalexpansion coefficient of the interposed sheet 81 can be reduced.Further, a material forming the interposed sheet 81 is preferably thesame as the material forming the deposition mask 20 in order to furtherreduce the difference between the thermal expansion coefficient of thedeposition mask 20 and the thermal expansion coefficient of theinterposed sheet 81. However, the material forming the interposed sheet81 and the material forming the deposition mask 20 may be different fromeach other as long as a difference between the thermal expansioncoefficients falls within the above-described range. For example, theinterposed sheet 81 may be formed of a 42 alloy (an iron alloycontaining 42% of nickel). The interposed sheet 81 may be made of amaterial containing a fiber material such as paper as long as theinterposed sheet 81 can be prevented from being caught by thethrough-hole 25 of the deposition mask 20. For example, the interposedsheet 81 may be made of acrylic-impregnated paper.

A thickness of the interposed sheet 81 is preferably 20 μm to 100 μm. Bysetting the thickness to 20 μm or larger, an uneven shape due to thethrough-hole 25 of the deposition mask 20 stacked on one surface of theinterposed sheet 81 can be prevented from appearing on the othersurface. In addition, it is possible to prevent the interposed sheet 81from breaking, and it is economical to also reuse the interposed sheet81. On the other hand, when the thickness is set to 100 μm or smaller,it is possible to reduce the mass of the interposed sheet 81 andsuppress an increase in the mass of the deposition mask package 60.

It is preferable that the interposed sheet 81 have such a dimension thata circumferential edge 81 a of the interposed sheet 81 can protrude fromthe deposition mask 20 over the entire circumference when viewed alongthe stacking direction of the deposition mask 20. In the presentembodiment, as illustrated in FIG. 33, a dimension (overall length inthe longitudinal direction) D5 of the interposed sheet 81 in thelongitudinal direction of the deposition mask 20 is larger than theoverall length D3 of the deposition mask 20 in the longitudinaldirection, and a dimension W4 of the interposed sheet 81 in the widthdirection of the deposition mask 20 is larger than the dimension W2 ofthe deposition mask 20 in the width direction. Thus, the interposedsheet 81 can protrude from the deposition mask 20 over the entirecircumference in the deposition mask stacked body 80, and it is possibleto prevent the deposition masks 20 adjacent to each other from beingbrought into direct contact and overlapping with each other. That is, ifthe overall length D5 of the interposed sheet 81 in the longitudinaldirection is smaller than the overall length D3 of the deposition mask20 in the longitudinal direction, the deposition mask 20 on one side ofthe interposed sheet 81 and the deposition mask 20 on the other side arebrought into direct contact and overlap with each other and there is apossibility that the through-hole 25 is deformed. Similarly, when thedimension W4 of the interposed sheet 81 in the width direction issmaller than the dimension W2 of the deposition mask 20 in the widthdirection, there is a possibility that the through-hole 25 is deformedin the same manner. However, it is possible to prevent the depositionmasks 20 on both the sides of the interposed sheet 81 from being broughtinto direct contact and overlapping with each other according to thepresent embodiment since the overall length D5 of the interposed sheet81 in the longitudinal direction is larger than the overall length D3 ofthe deposition mask 20 in the longitudinal direction, and the dimensionW4 of the interposed sheet 81 in the width direction is larger than thedimension W2 of the deposition mask 20 in the width direction.Therefore, the deformation of the through-hole 25 can be effectivelyprevented. Incidentally, the dimension W4 of the interposed sheet 81 inthe width direction is preferably smaller than the dimension W1 of theconcave portion 69 in the width direction.

As illustrated in FIGS. 28 and 29, the receiving portion 61 and the lidportion 62 sandwiching the deposition mask stacked body 80 are sealed bya sealing bag 73. The inside of the sealing bag 73 is evacuated anddecompressed. In addition, a desiccant 74 (for example, silica gel) iscontained in the sealing bag 73, the desiccant 74 adsorbs moisture inthe sealing bag 73 to maintain a dry state of the atmosphere in thesealing bag 73. As a result, the deposition mask 20 is prevented fromdeteriorating due to moisture. Incidentally, FIG. 27 does not illustratethe sealing bag 73.

As illustrated in FIGS. 28 and 29, the deposition mask package 60according to the present embodiment may include an impact sensor 75 thatdetects an impact applied to the deposition mask 20. In this case, theimpact applied to the deposition mask 20 during transportation can beconfirmed after the transportation. Therefore, when an impact equal toor larger than a predetermined value is applied during transportation,it is possible to estimate a possibility that a defect may occur in thedeposition mask 20 so that it is possible to improve the transportationquality of the deposition mask 20. As illustrated in FIGS. 28 and 29, itis preferable that the sealing bag 73 be accommodated in a cardboard box76, and the impact sensor 75 be mounted in a wooden box 77 packing thecardboard box 76, but it is not limited thereto. As the impact sensor75, for example, a shock watch label L-30 (green) manufactured bySHOCKWATCH Inc. can be suitably used.

Next, an operation of the present embodiment having such a configurationwill be described. Here, a method of packaging the deposition mask 20will be described.

(Deposition Mask Packaging Method)

First, the deposition mask 20 is prepared as described above, and thepackaging member 65 constituted by the receiving portion 61 and the lidportion 62 is prepared as illustrated in FIG. 34. At this time, thefirst flexible film 70 is pasted to the first opposing surface 68 of thereceiving portion 61 so as to cover the concave portion 69 of thereceiving portion 61, and the second flexible film 72 is pasted to thesecond opposing surface 71 of the lid portion 62. Incidentally, thefirst flexible film 70 and the second flexible film 72 may be reused aslong as it is regarded that there is no problem for the use such asalteration.

Next, the deposition mask stacked body 80 placed on the receivingportion 61 of the packaging member 65 is obtained as illustrated in FIG.35.

In this case, the interposed sheet 81 is first placed on the firstflexible film 70. The interposed sheet 81 is arranged at such a positionas to overlap with the deposition mask 20 described later.

Subsequently, the deposition mask 20 is placed on the interposed sheet81. That is, the deposition mask 20 is placed on the first flexible film70 with the interposed sheet 81 interposed therebetween. In this case,all the effective regions 22 of the deposition masks 20 are arranged onthe concave portion 69 with the first flexible film 70 interposedtherebetween, and the end 20 e of the deposition mask 20 is arranged onthe first opposing surface 68.

Next, the interposed sheet 81 is placed on the deposition mask 20. Thus,the interposed sheet 81 is stacked on the first surface 20 a and thesecond surface 20 b of the deposition mask 20. The interposed sheet 81in this case is arranged so as to overlap with the interposed sheet 81on a bottom surface of the deposition mask 20 when viewed along thestacking direction.

Thereafter, the placement of the deposition mask 20 and the placement ofthe interposed sheet 81 are repeated in the above-described manner,whereby the plurality of deposition masks 20 and the plurality ofinterposed sheets 81 are alternately stacked. Further, the interposedsheet 81 is placed on the deposition mask 20 that has been finallystacked, and the lowermost stage and the uppermost stage of thedeposition mask stacked body 80 become the interposed sheets 81 (seeFIGS. 31 and 32).

After obtaining the deposition mask stacked body 80 placed on thereceiving portion 61, the lid portion 62 is arranged on the depositionmask stacked body 80 as illustrated in FIG. 36. In this case, thepackaging member 65 is folded via the hinge portion 64, and the lidportion 62 is arranged above the deposition mask stacked body 80. As aresult, the receiving portion 61 and the lid portion 62 face each other,and the receiving portion 61 and the lid portion 62 are arranged on boththe sides of the deposition mask stacked body 80 in the verticaldirection.

Next, the deposition mask stacked body 80 is sandwiched between thereceiving portion 61 and the lid portion 62 as illustrated in FIG. 37.In this case, the receiving portion 61 and the lid portion 62 are boundby the elastic belt 63. For example, the two elastic belts 63 areattached at different positions in the longitudinal direction of thedeposition mask 20 (see FIG. 27). As a result, the receiving portion 61and the lid portion 62 are bound, and the deposition mask stacked body80 is held between the receiving portion 61 and the lid portion 62 bythe elastic force of the elastic belt 63. More specifically, not theentire deposition mask 20 but the ends 20 e on both the sides of thedeposition mask 20 in the longitudinal direction are sandwiched betweenthe receiving portion 61 and the lid portion 62. At this time, a gapcaused by the thickness of the deposition mask stacked body 80 is formedbetween the first opposing surface 68 of the receiving portion 61 andthe second opposing surface 71 of the lid portion 62.

The deposition mask stacked body 80 is subjected to a vertical force bythe elastic force of the elastic belt 63. In the end 20 e of thedeposition mask 20, this force is supported by the first opposingsurface 68 of the receiving portion 61 and the second opposing surface71 of the lid portion 62. Meanwhile, since the effective region 22 ofthe deposition mask 20 is arranged on the concave portion 69, theeffective region 22 of the deposition mask 20 is deflected downward dueto a downward force received from the second opposing surface 71 of thelid portion 62 as illustrated in FIG. 39. Since the deposition mask 20is supported by the first flexible film 70 on the concave portion 69,the first flexible film 70 suppresses the deflection of the depositionmask 20, thereby suppressing the deformation of the deposition mask 20.Thus, it is possible to reduce the amount of deformation of thedeposition mask 20 and to keep the deformation within an elasticdeformation range. Thus, the deposition mask 20 can be restored to itsoriginal shape (shape before being packaged) by its own elastic forceafter unpacking by removing the elastic belt 63.

In addition, since the interposed sheet 81 is interposed between thedeposition masks 20, it is avoided that the deposition masks 20 adjacentto each other are brought into direct contact and overlap with eachother. Thus, the deposition masks 20 that have received the downwardforce are prevented from meshing with each other in the effective region22 including a large number of the through-holes 25, and the depositionmask 20 can be not only smoothly deformed downward but also smoothlyrestored.

After the deposition mask stacked body 80 is sandwiched, the packagingmember 65 is sealed by the sealing bag 73 as illustrated in FIG. 38. Inthis case, the packaging member 65 is accommodated in the sealing bag 73together with the desiccant 74. Subsequently, the inside of the sealingbag 73 is evacuated through an opening. When the pressure inside thesealing bag 73 decreases to a predetermined degree of vacuum, theopening of the sealing bag 73 is sealed.

As illustrated in FIGS. 28 and 29, the packaging member 65 sealed withthe sealing bag 73 is accommodated in the cardboard box 76, and thecardboard box 76 is packaged with the wooden box 77. At this time, theimpact sensor 75 is mounted in the wooden box 77. In this manner, thedeposition mask package 60 according to the present embodiment isobtained.

Next, the case of transporting the deposition mask package 60 obtainedin the above-described manner will be described.

An impact may be applied to the deposition mask 20 while the depositionmask package 60 is being transported. For example, when a downward forceis applied to the deposition mask 20 by such an impact, the effectiveregion 22 of the deposition mask 20 is deflected downward by thedownward force as illustrated in FIG. 39. Since the deposition mask 20is supported by the first flexible film 70 on the concave portion 69 asdescribed above, the deformation of the deposition mask 20 issuppressed. Therefore, the deformation of the deposition mask 20 can bekept within the elastic deformation range, and the plastic deformationof the deposition mask 20 can be prevented even when receiving theimpact during transportation.

In addition, since the interposed sheet 81 is interposed between thedeposition masks 20, it is avoided that the deposition masks 20 adjacentto each other are brought into direct contact and overlap with eachother. Therefore, even when receiving shocks during transportation, itis possible to prevent the deposition masks 20 from meshing with eachother in the effective region 22 and to prevent the deposition masks 20adjacent to each other from being rubbed. In this manner, the plasticdeformation of the deposition mask 20 can be prevented.

There is a case where the temperature of the deposition mask package 60changes due to changes in the surrounding environment duringtransportation. In this case, each of the deposition mask 20 and theinterposed sheet 81 stretches or contracts. Meanwhile, the differencebetween the thermal expansion coefficient of the deposition mask 20 andthe thermal expansion coefficient of the interposed sheet 81 is set to 7ppm/° C. or less in the present embodiment. As a result, it is possibleto reduce a difference between a dimensional change (stretching orcontraction) of the deposition mask 20 and a dimensional change(stretching or contraction) of the interposed sheet 81. Thus, it ispossible to prevent wrinkles and scratches from being formed on thedeposition mask 20 due to positional deviation between the depositionmask 20 and the interposed sheet 81, and the plastic deformation of thedeposition mask 20 can be prevented.

In the case of unpacking the deposition mask package 60 aftertransportation, it is sufficient to follow a procedure opposite to thatof the above-described packaging method of the deposition mask 20. Inparticular, since the interposed sheet 81 is interposed between theadjacent deposition masks 20, the deposition mask 20 is prevented frommeshing with the deposition mask 20 arranged below the former depositionmask 20. Thus, it is possible to take out the individual depositionmasks 20 smoothly from the deposition mask stacked body 80. Thus, theplastic deformation of the deposition mask 20 can be prevented, and thehandling property of the deposition mask 20 can be improved.

According to the present embodiment, the difference between the thermalexpansion coefficient of the deposition mask 20 and the thermalexpansion coefficient of the interposed sheet 81 is 7 ppm/° C. or lessas described above. As a result, the difference between the thermalexpansion coefficient of the deposition mask 20 and the thermalexpansion coefficient of the interposed sheet 81 can be reduced. Thus,even when the temperature of the deposition mask package 60 changes dueto the changes in the surrounding environment during transportation, itis possible to reduce the difference between the dimensional change ofthe deposition mask 20 and the dimensional change of the interposedsheet 81. As a result, it is possible to prevent the wrinkles andscratches, which may be caused by the difference in dimensional change,from being formed on the deposition mask 20 and the interposed sheet 81,and to prevent the plastic deformation of the deposition mask 20.

In addition, the effective region 22 of the deposition mask 20 isarranged on the concave portion 69 of the receiving portion 61 with thefirst flexible film 70 interposed therebetween according to the presentembodiment. As a result, the effective region 22 of the deposition mask20 can be supported by the first flexible film 70. Therefore, it ispossible to suppress the deformation of the effective region 22deflected downward due to the downward force applied to the effectiveregion 22 of the deposition mask 20. Therefore, the deformation of thedeposition mask 20 can be kept within the elastic deformation range, andthe plastic deformation of the deposition mask 20 can be prevented.

In addition, since the dimension W4 of the interposed sheet 81 in thewidth direction is smaller than the dimension W1 of the concave portion69 in the width direction according to the present embodiment, theplastic deformation of the deposition mask 20 can be suppressed.

When the dimension W4 of the interposed sheet 81 in the width directionis equal to or larger than the dimension W1 of the concave portion 69 inthe width direction as illustrated in FIG. 40, it is conceivable a casewhere the deposition mask 20 is plastically deformed due to a shock orthe like during transportation. That is, the circumferential edge 81 aof the interposed sheet 81 is arranged on the outer side of the concaveportion 69 over the entire circumference, and a part of the interposedsheet 81 on the outer side in the width direction of the concave portion69 is arranged on the first opposing surface 68 of the receiving portion61 in the example illustrated in FIG. 40. When receiving a downwardforce in FIG. 39, the part of the interposed sheet 81 above the concaveportion 69 is deflected downward together with the first flexible film70 and the deposition mask 20. There is a case where a recess 81X suchas a wrinkle as illustrated in FIG. 40 is formed in the deflected partof the interposed sheet 81. The recess 81X is transferred to thedeposition mask 20 in contact with the interposed sheet 81, and thedeposition mask 20 is plastically deformed. The recess 81X tends to bemore easily formed as the material of the interposed sheet 81 is softer(more specifically, as the proof stress decreases), and more easilyformed as the thickness decreases. Incidentally, when a relatively hardmaterial such as PET is used for the first flexible film 70, it ispossible to prevent the formation of the recess in the first flexiblefilm 70, but the recess 81X may be formed in the interposed sheet 81even when the recess is not formed in the first flexible film 70.

On the other hand, since the dimension W4 of the interposed sheet 81 inthe width direction is smaller than the dimension W1 of the concaveportion 69 in the width direction as illustrated in FIG. 33 according tothe present embodiment, the portion of the interposed sheet 81 on theconcave portion 69 is arranged on the concave portion 69 over the entirewidth direction of the interposed sheet 81. As a result, the portion ofthe interposed sheet 81 on the concave portion 69 is deflected so as toenter the concave portion 69 over the entire width direction whenreceiving a downward force. Thus, it is possible to prevent theformation of the recess 81X as illustrated in FIG. 40 and to prevent theplastic deformation of the deposition mask 20.

Although the embodiment of the present invention has been described indetail as above, the deposition mask package and the deposition maskpackaging method according to the embodiment of the present inventionare not limited to the above-described embodiment, and variousmodifications can be made in a scope not departing from a gist of thepresent invention.

In the above-described embodiment, the example in which the receivingportion 61 and the lid portion 62 are connected via the hinge portion 64and integrally formed has been described. However, it is not limitedthereto, and the receiving portion 61 and the lid portion 62 may beformed separately as illustrated in FIG. 41. Even in this case, thereceiving portion 61 and the lid portion 62 can be bound with theelastic belt 63, and the deposition mask stacked body 80 can be heldbetween the receiving portion 61 and the lid portion 62.

In addition, the example in which the deposition mask stacked body 80sandwiched between the receiving portion 61 and the lid portion 62includes the plurality of deposition masks 20 has been described in theabove-described embodiment. However, it is not limited thereto, and thedeposition mask stacked body 80 may be constituted by one depositionmask 20 and two interposed sheets 81 stacked on the first surface 20 aand the second surface 20 b of the deposition mask 20. Even in thiscase, it is possible to prevent other members from being caught by thethrough-hole 25 of the deposition mask 20, and to prevent the plasticdeformation of the deposition mask 20.

In addition, the example in which the interposed sheet 81 and thedeposition mask 20 are alternately stacked on the receiving portion 61of the packaging member 65 to form the deposition mask stacked body 80has been described in the above-described embodiment. However, it is notlimited thereto, and the deposition mask stacked body 80 may be placedon the receiving portion 61 after forming the deposition mask stackedbody 80 in advance.

EXAMPLES

A transportation test of the deposition mask package 60 packing thedeposition mask 20 was carried out using various interposed sheets 81and states of the deposition masks 20 after transportation wereconfirmed.

As the deposition masks 20 used in the transportation test, thedeposition masks 20 having various thickness T0 were used as illustratedin FIG. 42. Each of the deposition masks 20 is the deposition mask 20manufactured by the etching process illustrated in FIGS. 4 to 19. Thedeposition mask 20 was made of an invar material containing 36% by massof nickel. In each of the deposition masks 20, the dimension W2 (seeFIG. 33) in the width direction was set to 67 mm and the overall lengthD3 in the longitudinal direction was set to 850 mm.

As illustrated in FIG. 42, sheets made of various materials were used asthe interposed sheet 81. More specifically, an invar material containing36% by mass of nickel was used for the interposed sheet 81 as Example 1,a 42 alloy was used as Example 2, and acrylic-impregnated paper was usedas Example 3. On the other hand, stainless steel (SUS 430) was used asComparative Example 1, high-molecular-weight polyethylene (PE) was usedas Comparative Example 2, polyethylene terephthalate (PET) was used asComparative Example 3, and low-molecular-weight polyethylene was used asComparative Example 4. A thermal expansion coefficient of each materialat 25° C. is set as illustrated in FIG. 42. FIG. 42 illustrates a valueobtained by subtracting the thermal expansion coefficient of thedeposition mask 20 (the invar material containing 36% by mass of nickel)from the thermal expansion coefficient of the interposed sheet 81. Thedimension W4 of each of the interposed sheets 81 in the width directionwas 150 mm, the overall length D5 in the longitudinal direction was 980mm, and the thickness was 75 μm.

Five deposition masks 20 and four interposed sheets 81 were alternatelystacked to produce the deposition mask package 60 according to the aboveembodiment. The deposition mask package 60 was prepared in a work roomwhose room temperature was controlled at 25° C.

The deposition mask package 60 thus produced was transported to adestination via a land route, an air route, and a land route. Thetemperature of the destination was −16° C., which is the lowesttemperature of the surrounding environment during transportation, andthe temperature of the deposition mask 20 was decreased to −16° C.before unpacking. The unpacking of the deposition mask package 60 wasperformed in a work room whose room temperature was controlled at 25° C.Incidentally, there is a possibility that the highest temperature in thesurrounding environment during transportation is higher than 25° C. Evenin such a case, it is considered that a temperature difference betweenthe temperature at the time of packaging and the highest air temperatureis smaller than a temperature difference between the temperature at thetime of packaging and the lowest air temperature. Thus, it wasconsidered that the deformation of the deposition mask 20 may beconfirmed by paying attention to the temperature difference between thetemperature at the time of packing and the lowest temperature, and thetransportation test was carried out.

After unpacking, it was confirmed visually (with naked eyes) whetherwavy wrinkles were formed and whether scratches were formed on each ofthe deposition masks 20. FIG. 42 illustrates results thereof. Here, amark ∘ indicates that neither a wrinkle nor a scratch were visuallyobserved on all of the five deposition masks 20, and a mark x indicatesthat at least one of the wrinkle and the scratch was visually confirmedin at least one deposition mask among the five deposition masks 20.

As illustrated in FIG. 42, when the difference between the thermalexpansion coefficient of the deposition mask 20 and the thermalexpansion coefficient of the interposed sheet 81 is 7 ppm/° C. or less,it has been confirmed that no wrinkle and scratch is formed on thedeposition masks 20 of all the thicknesses. That is, the formation ofwrinkles and scratches on the deposition mask 20 can be suppressed bysetting the difference in thermal expansion coefficient to 7 ppm/° C. orless, and the plastic deformation of the deposition mask 20 can beprevented. If the thickness of the deposition mask 20 is 15 μm orlarger, it is considered that the strength of the deposition mask 20itself can be secured so that the formation of wrinkles on thedeposition mask 20 can be further suppressed.

Incidentally, the deposition mask 20 manufactured by the etching processis used in the present embodiment, but it is considered that at leastthe same results can be obtained even for the deposition mask 20produced by the plating process. That is, the metal plate 21 produced asa rolled material is used for the deposition mask 20 of the etchingprocess as described above, but a crystal of the deposition mask 20produced by the plating process is finer than a crystal of the metalplate 21. As a result, the hardness and proof stress of the depositionmask 20 produced by the plating process are larger than those of themetal plate 21. Therefore, even when the deposition mask 20 produced bythe plating process is used, it is considered that results equivalent toor greater than those of the present embodiment can be obtained, and theformation of wrinkles and scratches can be further suppressed.

1. A deposition mask package comprising: a receiving portion; a lidportion that faces the receiving portion; a deposition mask that isarranged between the receiving portion and the lid portion and has aneffective region in which a plurality of through-holes is formed,wherein the receiving portion has a first opposing surface facing thelid portion and a concave portion provided on the first opposingsurface, the concave portion is covered with a first flexible film, andthe effective region of the deposition mask is arranged on the concaveportion with the first flexible film interposed therebetween.
 2. Thedeposition mask package according to claim 1, wherein ends on both sidesin a first direction of the deposition mask are arranged on the firstopposing surface of the receiving portion.
 3. The deposition maskpackage according to claim 2, wherein a dimension of the concave portionin a second direction orthogonal to the first direction is larger than adimension of the deposition mask in the second direction.
 4. Thedeposition mask package according to claim 2, wherein an interposedsheet is interposed between the deposition mask and the first flexiblefilm, and a dimension of the interposed sheet in a second directionorthogonal to the first direction is smaller than a dimension of theconcave portion in the second direction.
 5. The deposition mask packageaccording to claim 1, wherein the first flexible film is a PET film. 6.The deposition mask package according to claim wherein the firstflexible film is antistatic-coated.
 7. The deposition mask packageaccording to claim 1, wherein a second flexible film is interposedbetween the lid portion and the deposition mask.
 8. The deposition maskpackage according to claim 1, wherein the receiving portion and the lidportion are connected via a hinge portion.
 9. The deposition maskpackage according to claim 1, further comprising a sealing bag thatseals the receiving portion and the lid portion.
 10. The deposition maskpackage according to claim 1, further comprising an impact sensor thatdetects an impact applied to the deposition mask.
 11. A deposition maskpackaging method for packaging a deposition mask having an effectiveregion in which a plurality of through-holes is formed, the depositionmask packaging method comprising: preparing a receiving portion that hasa first opposing surface and a concave portion provided on the firstopposing surface and covered with a first flexible film; obtaining thedeposition mask placed on the receiving portion; arranging a lid portionon the deposition mask such that the receiving portion and the lidportion face each other; and sandwiching the deposition mask between thereceiving portion and the lid portion, wherein the effective region ofthe deposition mask is placed on the concave portion with the firstflexible film interposed therebetween in the arranging of the depositionmask.
 12. A deposition mask package comprising: a receiving portion; alid portion that faces the receiving portion; and a deposition maskstacked body arranged between the receiving portion and the lid portion,wherein the deposition mask stacked body includes: a deposition maskhaving a first surface, a second surface positioned opposite to thefirst surface, and a plurality of through-holes extending from the firstsurface to the second surface; and a plurality of interposed sheetsstacked on the first surface and the second surface of the depositionmask, and a difference between a thermal expansion coefficient of thedeposition mask and the thermal expansion coefficient of the interposedsheet is 7 ppm/° C. or less.
 13. The deposition mask package accordingto claim 12, wherein the interposed sheet has a dimension that enables acircumferential edge of the interposed sheet to protrude from thedeposition mask over an entire circumference as viewed along a stackingdirection of the deposition mask.
 14. The deposition mask packageaccording to claim 12, wherein the deposition mask and the interposedsheet are formed using an iron alloy containing nickel in an amount of30% by mass to 54% by mass.
 15. The deposition mask package according toclaim 12, wherein the deposition mask and the interposed sheet areformed using an iron alloy containing chromium.
 16. The deposition maskpackage according to claim 12, wherein a material forming the interposedsheet is identical to a material forming the deposition mask.
 17. Thedeposition mask package according to claim 12, wherein a thickness ofthe interposed sheet is 20 μm to 100 μm.
 18. The deposition mask packageaccording to claim 12, wherein the thickness of the deposition mask is15 μm or more.
 19. The deposition mask package according to claim 12,wherein the receiving portion has a first opposing surface facing thelid portion and a concave portion provided on the first opposingsurface, ends on both sides in a first direction of the deposition maskare arranged on the first opposing surface of the receiving portion, adimension of the interposed sheet in a second direction orthogonal tothe first direction is smaller than a dimension of the concave portionin the second direction.
 20. A deposition mask packaging method forpackaging a deposition mask, which includes a first surface, a secondsurface positioned opposite to the first surface, and a plurality ofthrough-holes extending from the first surface to the second surface,the deposition mask packaging method comprising: obtaining a depositionmask stacked body having the deposition mask and an interposed sheetstacked on the first surface and the second surface of the depositionmask, the deposition mask stacked body placed on the receiving portion;arranging a lid portion on the deposition mask stacked body such thatthe receiving portion and the lid portion face each other; andsandwiching the deposition mask stacked body between the receivingportion and the lid portion, wherein a difference between a thermalexpansion coefficient of the deposition mask and a thermal expansioncoefficient of the interposed sheet is 7 ppm/° C. or less.